diff --git a/mrbgems/mruby-bin-debugger/tools/mrdb/cmdmisc.c b/mrbgems/mruby-bin-debugger/tools/mrdb/cmdmisc.c
index 4cf635b41..36fb0c1fa 100644
--- a/mrbgems/mruby-bin-debugger/tools/mrdb/cmdmisc.c
+++ b/mrbgems/mruby-bin-debugger/tools/mrdb/cmdmisc.c
@@ -501,9 +501,7 @@ dbgcmd_quit(mrb_state *mrb, mrdb_state *mrdb)
   }
 
   if (mrdb->dbg->xm == DBG_QUIT) {
-    struct RClass *exc;
-    exc = mrb_define_class(mrb, "DebuggerExit", E_EXCEPTION);
-    mrb_raise(mrb, exc, "Exit mrdb");
+    raise_debugger_exception(mrb, "DebuggerExit", "Exit mrdb");
   }
   return DBGST_PROMPT;
 }
diff --git a/mrbgems/mruby-bin-debugger/tools/mrdb/cmdrun.c b/mrbgems/mruby-bin-debugger/tools/mrdb/cmdrun.c
index 1cd463eb0..dd914af77 100644
--- a/mrbgems/mruby-bin-debugger/tools/mrdb/cmdrun.c
+++ b/mrbgems/mruby-bin-debugger/tools/mrdb/cmdrun.c
@@ -17,10 +17,8 @@ dbgcmd_run(mrb_state *mrb, mrdb_state *mrdb)
   else {
     dbg->xm = DBG_QUIT;
     if (dbg->xphase == DBG_PHASE_RUNNING){
-      struct RClass *exc;
       puts("Start it from the beginning");
-      exc = mrb_define_class(mrb, "DebuggerRestart", E_EXCEPTION);
-      mrb_raise(mrb, exc, "Restart mrdb");
+      raise_debugger_exception(mrb, "DebuggerRestart", "Restart mrdb");
     }
   }
 
diff --git a/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.h b/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.h
index 1d379f4c7..df7680aff 100644
--- a/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.h
+++ b/mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.h
@@ -7,6 +7,7 @@
 #define MRDB_H
 
 #include <mruby.h>
+#include <mruby/class.h>
 
 #include "mrdbconf.h"
 
@@ -136,6 +137,13 @@ typedef struct mrdb_state {
 
 typedef dbgcmd_state (*debug_command_func)(mrb_state*, mrdb_state*);
 
+static inline mrb_noreturn void
+raise_debugger_exception(mrb_state *mrb, const char *name, const char *msg)
+{
+  struct RClass *exc = mrb_define_class(mrb, name, E_EXCEPTION);
+  mrb_raise(mrb, exc, msg);
+}
+
 /* cmdrun.c */
 dbgcmd_state dbgcmd_run(mrb_state*, mrdb_state*);
 dbgcmd_state dbgcmd_continue(mrb_state*, mrdb_state*);