diff --git a/include/mruby/internal.h b/include/mruby/internal.h
index 17e867d7b..1f991c414 100644
--- a/include/mruby/internal.h
+++ b/include/mruby/internal.h
@@ -88,6 +88,7 @@ mrb_value mrb_complex_add(mrb_state *mrb, mrb_value x, mrb_value y);
 mrb_value mrb_complex_sub(mrb_state *mrb, mrb_value x, mrb_value y);
 mrb_value mrb_complex_mul(mrb_state *mrb, mrb_value x, mrb_value y);
 mrb_value mrb_complex_div(mrb_state *mrb, mrb_value x, mrb_value y);
+void mrb_complex_copy(mrb_state *mrb, mrb_value x, mrb_value y);
 #endif
 #ifdef MRB_USE_RATIONAL
 mrb_value mrb_rational_new(mrb_state *mrb, mrb_int x, mrb_int y);
diff --git a/mrbgems/mruby-bin-mrbc/tools/mrbc/stub.c b/mrbgems/mruby-bin-mrbc/tools/mrbc/stub.c
index 1513471c1..13ca03932 100644
--- a/mrbgems/mruby-bin-mrbc/tools/mrbc/stub.c
+++ b/mrbgems/mruby-bin-mrbc/tools/mrbc/stub.c
@@ -34,6 +34,9 @@ mrb_value mrb_complex_to_f(mrb_state *mrb, mrb_value x)
 {
   return mrb_nil_value();
 }
+void mrb_complex_copy(mrb_state *mrb, mrb_value x, mrb_value y)
+{
+}
 #endif
 
 #ifdef MRB_USE_RATIONAL
diff --git a/mrbgems/mruby-complex/src/complex.c b/mrbgems/mruby-complex/src/complex.c
index 7cc82177d..55f7412b8 100644
--- a/mrbgems/mruby-complex/src/complex.c
+++ b/mrbgems/mruby-complex/src/complex.c
@@ -84,6 +84,15 @@ mrb_complex_new(mrb_state *mrb, mrb_float real, mrb_float imaginary)
 
 #define complex_new(mrb, real, imag) mrb_complex_new(mrb, real, imag)
 
+void
+mrb_complex_copy(mrb_state *mrb, mrb_value x, mrb_value y)
+{
+  struct mrb_complex *p1 = complex_ptr(mrb, x);
+  struct mrb_complex *p2 = complex_ptr(mrb, y);
+  p1->real = p2->real;
+  p1->imaginary = p2->imaginary;
+}
+
 static mrb_value
 complex_real(mrb_state *mrb, mrb_value self)
 {
diff --git a/src/class.c b/src/class.c
index 581a1a859..c2581be9a 100644
--- a/src/class.c
+++ b/src/class.c
@@ -2747,6 +2747,11 @@ init_copy(mrb_state *mrb, mrb_value dest, mrb_value obj)
       mrb_rational_copy(mrb, dest, obj);
       break;
 #endif
+#ifdef MRB_USE_COMPLEX
+    case MRB_TT_COMPLEX:
+      mrb_complex_copy(mrb, dest, obj);
+      break;
+#endif
 
     default:
       break;