diff --git a/hrplib/hrpUtil/EigenTypes.h b/hrplib/hrpUtil/EigenTypes.h
index cd25f14a3..bd0d42154 100644
--- a/hrplib/hrpUtil/EigenTypes.h
+++ b/hrplib/hrpUtil/EigenTypes.h
@@ -20,26 +20,4 @@ namespace hrp{
 #include <iostream>
 #include <iomanip>
 
-inline std::ostream& operator<<(std::ostream& out, hrp::dmatrix &a) {
-    const int c = a.rows();
-    const int n = a.cols();
-
-    for(int i = 0; i < c; i++){
-        out << "      :";
-        for(int j = 0; j < n; j++){
-            out << " " << std::setw(7) << std::setiosflags(std::ios::fixed) << std::setprecision(4) << (a)(i,j);
-        }
-        out << std::endl;
-    }
-}
-
-inline std::ostream& operator<<(std::ostream& out, hrp::dvector &a) {
-    const int n = a.size();
-
-    for(int i = 0; i < n; i++){
-        out << std::setw(7) << std::setiosflags(std::ios::fixed) << std::setprecision(4) << a(i) << " ";
-    }
-    out << std::endl;
-}
-
 #endif
diff --git a/hrplib/hrpUtil/MatrixSolvers.cpp b/hrplib/hrpUtil/MatrixSolvers.cpp
index d9f1fb1da..01c0b3674 100644
--- a/hrplib/hrpUtil/MatrixSolvers.cpp
+++ b/hrplib/hrpUtil/MatrixSolvers.cpp
@@ -46,6 +46,28 @@ extern "C" void dgeev_(char const*jobvl, char const*jobvr, int *n, double *A,
 					  int *ldvl, double *vr, int *ldvr, double *work, int *lwork, int *info);
 
 
+inline std::ostream& operator<<(std::ostream& out, hrp::dmatrix &a) {
+    const int c = a.rows();
+    const int n = a.cols();
+
+    for(int i = 0; i < c; i++){
+        out << "      :";
+        for(int j = 0; j < n; j++){
+            out << " " << std::setw(7) << std::setiosflags(std::ios::fixed) << std::setprecision(4) << (a)(i,j);
+        }
+        out << std::endl;
+    }
+}
+
+inline std::ostream& operator<<(std::ostream& out, hrp::dvector &a) {
+    const int n = a.size();
+
+    for(int i = 0; i < n; i++){
+        out << std::setw(7) << std::setiosflags(std::ios::fixed) << std::setprecision(4) << a(i) << " ";
+    }
+    out << std::endl;
+}
+
 // originally in hrpCLAPACK.{cpp,h}
 // solveLinearEquation()
 // b = a * x, x = b^(-1) * a