diff --git a/SMILEBASIC/VM.d b/SMILEBASIC/VM.d
index 0381cb3..3b0ee1c 100644
--- a/SMILEBASIC/VM.d
+++ b/SMILEBASIC/VM.d
@@ -1560,7 +1560,15 @@ class CallBuiltinFunction : Code
             arg = vm.stack[vm.stacki - argcount..vm.stacki];
             result = vm.stack[vm.stacki/* - argcount */+ 1..vm.stacki + 1/* - argcount */+ outcount];//雑;
         }
-        func.func(vm.petitcomputer, arg, result);
+        try
+        {
+            func.func(vm.petitcomputer, arg, result);
+        }
+        catch (SmileBasicError sbe)
+        {
+            sbe.func = func.name;
+            throw sbe;
+        }
         if(func.variadic)
         {
             vm.stacki -= argcount;
diff --git a/SMILEBASIC/error.d b/SMILEBASIC/error.d
index e2f6b91..872949f 100644
--- a/SMILEBASIC/error.d
+++ b/SMILEBASIC/error.d
@@ -10,6 +10,7 @@ class SmileBasicError : Exception
     int errline;
     int errprg;
     string message2;
+    string func;
     this(int slot, int line, string message)
     {
         super(format("%s in %d:%d", message, slot, line));
diff --git a/SMILEBASIC/petitcomputer.d b/SMILEBASIC/petitcomputer.d
index bb22290..aca3e8f 100644
--- a/SMILEBASIC/petitcomputer.d
+++ b/SMILEBASIC/petitcomputer.d
@@ -1230,6 +1230,7 @@ class PetitComputer
                             //print(sbe.to!string);
                             writeln(sbe.to!string);
                             writeln(sbe.getErrorMessage2);
+                            writeln(sbe.func);
                             loc = vm.currentLocation;
                             console.print(loc.line, ":", loc.pos, ":", parser.getLine(loc));
                         }