diff --git a/lib/fluent/log/console_adapter.rb b/lib/fluent/log/console_adapter.rb
new file mode 100644
index 0000000000..9c8ecf482e
--- /dev/null
+++ b/lib/fluent/log/console_adapter.rb
@@ -0,0 +1,66 @@
+#
+# Fluentd
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+#
+
+require 'console/terminal/logger'
+
+module Fluent
+  class Log
+    # Async gem which is used by http_server helper switched logger mechanism to
+    # Console gem which isn't complatible with Ruby's standard Logger (since
+    # v1.17). This class adapts it to Fluentd's logger mechanism.
+    class ConsoleAdapter < Console::Terminal::Logger
+      def self.wrap(logger)
+        _, level = Console::Logger::LEVELS.find { |key, value|
+          if logger.level <= 0
+            key == :debug
+          else
+            value == logger.level - 1
+          end
+        }
+        Console::Logger.new(ConsoleAdapter.new(logger), level: level)
+      end
+
+      def initialize(logger)
+        @logger = logger
+        # When `verbose` is `true`, following items will be added as a prefix or
+        # suffix of the subject:
+        #   * Severity
+        #   * Object ID
+        #   * PID
+        #   * Time
+        # Severity and Time are added by Fluentd::Log too so they are redundant.
+        # PID is the worker's PID so it's also redundant.
+        # Object ID will be too verbose in usual cases.
+        # So set it as `false` here to suppress redundant items.
+        super(StringIO.new, verbose: false)
+      end
+
+      def call(subject = nil, *arguments, name: nil, severity: 'info', **options, &block)
+        if LEVEL_TEXT.include?(severity.to_s)
+          level = severity
+        else
+          @logger.warn("Unknown severity: #{severity}")
+          level = 'warn'
+        end
+
+        @io.seek(0)
+        @io.truncate(0)
+        super
+        @logger.send(level, @io.string.chomp)
+      end
+    end
+  end
+end
diff --git a/lib/fluent/plugin_helper/http_server/server.rb b/lib/fluent/plugin_helper/http_server/server.rb
index 4266bc639f..549db76cc8 100644
--- a/lib/fluent/plugin_helper/http_server/server.rb
+++ b/lib/fluent/plugin_helper/http_server/server.rb
@@ -21,6 +21,7 @@
 require 'fluent/plugin_helper/http_server/app'
 require 'fluent/plugin_helper/http_server/router'
 require 'fluent/plugin_helper/http_server/methods'
+require 'fluent/log/console_adapter'
 
 module Fluent
   module PluginHelper
@@ -38,7 +39,7 @@ def initialize(addr:, port:, logger:, default_app: nil, tls_context: nil)
           scheme = tls_context ? 'https' : 'http'
           @uri = URI("#{scheme}://#{@addr}:#{@port}").to_s
           @router = Router.new(default_app)
-          @reactor = Async::Reactor.new(nil, logger: @logger)
+          @reactor = Async::Reactor.new(nil, logger: Fluent::Log::ConsoleAdapter.wrap(@logger))
 
           opts = if tls_context
                    { ssl_context: tls_context }
diff --git a/test/log/test_console_adapter.rb b/test/log/test_console_adapter.rb
new file mode 100644
index 0000000000..06d9d900ad
--- /dev/null
+++ b/test/log/test_console_adapter.rb
@@ -0,0 +1,110 @@
+require_relative '../helper'
+
+require 'fluent/log'
+require 'fluent/log/console_adapter'
+
+class ConsoleAdapterTest < Test::Unit::TestCase
+  def setup
+    @timestamp = Time.parse("2023-01-01 15:32:41 +0000")
+    @timestamp_str = @timestamp.strftime("%Y-%m-%d %H:%M:%S %z")
+    Timecop.freeze(@timestamp)
+
+    @logdev = Fluent::Test::DummyLogDevice.new
+    @logger = ServerEngine::DaemonLogger.new(@logdev)
+    @fluent_log = Fluent::Log.new(@logger)
+    @console_logger = Fluent::Log::ConsoleAdapter.wrap(@fluent_log)
+  end
+
+  def teardown
+    Timecop.return
+  end
+
+  def test_expected_log_levels
+    assert_equal({debug: 0, info: 1, warn: 2, error: 3, fatal: 4},
+                 Console::Logger::LEVELS)
+  end
+
+  data(trace: [Fluent::Log::LEVEL_TRACE, :debug],
+       debug: [Fluent::Log::LEVEL_DEBUG, :debug],
+       info: [Fluent::Log::LEVEL_INFO, :info],
+       warn: [Fluent::Log::LEVEL_WARN, :warn],
+       error: [Fluent::Log::LEVEL_ERROR, :error],
+       fatal: [Fluent::Log::LEVEL_FATAL, :fatal])
+  def test_reflect_log_level(data)
+    level, expected = data
+    @fluent_log.level = level
+    console_logger = Fluent::Log::ConsoleAdapter.wrap(@fluent_log)
+    assert_equal(Console::Logger::LEVELS[expected],
+                 console_logger.level)
+  end
+
+  data(debug: :debug,
+       info: :info,
+       warn: :warn,
+       error: :error,
+       fatal: :fatal)
+  def test_string_subject(level)
+    @console_logger.send(level, "subject")
+    assert_equal(["#{@timestamp_str} [#{level}]:   0.0s: subject\n"],
+                 @logdev.logs)
+  end
+
+  data(debug: :debug,
+       info: :info,
+       warn: :warn,
+       error: :error,
+       fatal: :fatal)
+  def test_args(level)
+    @console_logger.send(level, "subject", 1, 2, 3)
+    assert_equal([
+                   "#{@timestamp_str} [#{level}]:   0.0s: subject\n" +
+                   "      | 1\n" +
+                   "      | 2\n" +
+                   "      | 3\n"
+                 ],
+                 @logdev.logs)
+  end
+
+  data(debug: :debug,
+       info: :info,
+       warn: :warn,
+       error: :error,
+       fatal: :fatal)
+  def test_options(level)
+    @console_logger.send(level, "subject", kwarg1: "opt1", kwarg2: "opt2")
+    assert_equal([
+                   "#{@timestamp_str} [#{level}]:   0.0s: subject\n" +
+                   "      | {\"kwarg1\":\"opt1\",\"kwarg2\":\"opt2\"}\n"
+                 ],
+                 @logdev.logs)
+  end
+
+  data(debug: :debug,
+       info: :info,
+       warn: :warn,
+       error: :error,
+       fatal: :fatal)
+  def test_block(level)
+    @console_logger.send(level, "subject") { "block message" }
+    assert_equal([
+                   "#{@timestamp_str} [#{level}]:   0.0s: subject\n" +
+                   "      | block message\n"
+                 ],
+                 @logdev.logs)
+  end
+
+  data(debug: :debug,
+       info: :info,
+       warn: :warn,
+       error: :error,
+       fatal: :fatal)
+  def test_multiple_entries(level)
+    @console_logger.send(level, "subject1")
+    @console_logger.send(level, "line2")
+    assert_equal([
+                   "#{@timestamp_str} [#{level}]:   0.0s: subject1\n",
+                   "#{@timestamp_str} [#{level}]:   0.0s: line2\n"
+                 ],
+                 @logdev.logs)
+  end
+end
diff --git a/test/plugin_helper/test_http_server_helper.rb b/test/plugin_helper/test_http_server_helper.rb
index 6691c9182d..4fd044bb0e 100644
--- a/test/plugin_helper/test_http_server_helper.rb
+++ b/test/plugin_helper/test_http_server_helper.rb
@@ -127,7 +127,7 @@ def start_https_request(addr, port, verify: true, cert_path: nil, selfsigned: tr
     end
 
     client = Async::HTTP::Client.new(Async::HTTP::Endpoint.parse("https://#{addr}:#{port}", ssl_context: context))
-    reactor = Async::Reactor.new(nil, logger: NULL_LOGGER)
+    reactor = Async::Reactor.new(nil, logger: Fluent::Log::ConsoleAdapter.wrap(NULL_LOGGER))
 
     resp = nil
     error = nil