diff --git a/lib/fluent/plugin/in_tail.rb b/lib/fluent/plugin/in_tail.rb
index 63ec165b96..0f9c3865dd 100644
--- a/lib/fluent/plugin/in_tail.rb
+++ b/lib/fluent/plugin/in_tail.rb
@@ -146,6 +146,10 @@ def configure(conf)
         raise Fluent::ConfigError, "cannot use glob_policy as always with the default path_delimitor: `,\""
       end
 
+      if @glob_policy == :extended && /\{.*,.*\}/.match(@path) && extended_glob_pattern(@path)
+        raise Fluent::ConfigError, "cannot include curly braces with glob patterns in `#{@path}\". Use glob_policy always instead."
+      end
+
       if RESERVED_CHARS.include?(@path_delimiter)
         rc = RESERVED_CHARS.join(', ')
         raise Fluent::ConfigError, "#{rc} are reserved words: #{@path_delimiter}"
@@ -289,13 +293,17 @@ def have_read_capability?
         @capability.have_capability?(:effective, :dac_override)
     end
 
+    def extended_glob_pattern(path)
+      path.include?('*') || path.include?('?') || /\[.*\]/.match(path)
+    end
+
     # Curly braces is not supported for now because the default delimiter of path is ",".
     # This should be collided for wildcard pattern for curly braces.
     def use_glob?(path)
       if @glob_policy == :always
-        path.include?('*') || path.include?('?') || /\[.*\]/.match(path) || /\{.*,.*\}/.match(path)
+        extended_glob_pattern(path) || /\{.*,.*\}/.match(path)
       elsif @glob_policy == :extended
-        path.include?('*') || path.include?('?') || /\[.*\]/.match(path)
+        extended_glob_pattern(path)
       elsif @glob_policy == :backward_compatible
         path.include?('*')
       end
diff --git a/test/plugin/test_in_tail.rb b/test/plugin/test_in_tail.rb
index 296386ffc6..7b302ab595 100644
--- a/test/plugin/test_in_tail.rb
+++ b/test/plugin/test_in_tail.rb
@@ -1540,11 +1540,12 @@ def test_expand_paths
 
     sub_test_case "expand_paths with glob" do |data|
       sub_test_case "extended_glob" do
-        data("square brackets"       => [true, "extended", "test/plugin/data/log_numeric/[0-1][2-4].log"],
-             "asterisk"              => [true, "extended", "test/plugin/data/log/*.log"],
-             "one character matcher" => [true, "extended", "test/plugin/data/log/tes?.log"],
+        data("curly braces"          => [true, "always", "test/plugin/data/log_numeric/{0,1}*.log"],
+             "square brackets"       => [true, "always", "test/plugin/data/log_numeric/[0-1][2-4].log"],
+             "asterisk"              => [true, "always", "test/plugin/data/log/*.log"],
+             "one character matcher" => [true, "always", "test/plugin/data/log/tes?.log"],
             )
-        def test_expand_paths_with_use_glob_p
+        def test_expand_paths_with_use_glob_p_and_almost_set_of_patterns
           result, option, path = data
           config = config_element("", "", {
                                     "tag" => "tail",
@@ -1554,12 +1555,41 @@ def test_expand_paths_with_use_glob_p
                                     "read_from_head" => true,
                                     "refresh_interval" => 30,
                                     "glob_policy" => option,
+                                    "path_delimiter" => "|",
                                     "rotate_wait" => "#{EX_ROTATE_WAIT}s",
                                     "follow_inodes" => "#{EX_FOLLOW_INODES}",
                                   })
           plugin = create_driver(config, false).instance
           assert_equal(result, !!plugin.use_glob?(path))
         end
+
+        data("curly braces"          => [true, false, "extended", "test/plugin/data/log_numeric/{0,1}*.log"],
+             "square brackets"       => [false, true, "extended", "test/plugin/data/log_numeric/[0-1][2-4].log"],
+             "asterisk"              => [false, true, "extended", "test/plugin/data/log/*.log"],
+             "one character matcher" => [false, true, "extended", "test/plugin/data/log/tes?.log"],
+            )
+        def test_expand_paths_with_use_glob_p
+          emit_exception_p, result, option, path = data
+          config = config_element("", "", {
+                                    "tag" => "tail",
+                                    "path" => path,
+                                    "format" => "none",
+                                    "pos_file" => "#{@tmp_dir}/tail.pos",
+                                    "read_from_head" => true,
+                                    "refresh_interval" => 30,
+                                    "glob_policy" => option,
+                                    "rotate_wait" => "#{EX_ROTATE_WAIT}s",
+                                    "follow_inodes" => "#{EX_FOLLOW_INODES}",
+                                  })
+          if emit_exception_p
+            assert_raise(Fluent::ConfigError) do
+              plugin = create_driver(config, false).instance
+            end
+          else
+            plugin = create_driver(config, false).instance
+            assert_equal(result, !!plugin.use_glob?(path))
+          end
+        end
       end
 
       sub_test_case "only_use_backward_compatible" do