diff --git a/SMILEBASIC/compiler.d b/SMILEBASIC/compiler.d
index 5c61720..2cad417 100644
--- a/SMILEBASIC/compiler.d
+++ b/SMILEBASIC/compiler.d
@@ -165,6 +165,8 @@ class Function
 class Compiler
 {
     bool isDirectMode;
+    bool isDefint;
+    bool isStrictMode;
     ValueType getType(wstring name)
     {
         wchar s = name[name.length - 1];
@@ -177,8 +179,10 @@ class Compiler
             case '%':
                 return ValueType.Integer;
             default:
-                return ValueType.Double;//非DEFINT時
-                //return ValueType.Integer;//DEFINT時
+                if (!isDefint)
+                    return ValueType.Double;//非DEFINT時
+                else
+                    return ValueType.Integer;//DEFINT時
         }
     }
     Statements statements;
@@ -437,6 +441,10 @@ class Compiler
         {
             //local変数をあたる
             //それでもだめならOPTION STRICTならエラー
+            if (isStrictMode)
+            {
+                throw new UndefinedVariable();
+            }
             this.global[name] = VMVariable(global = ++globalIndex, getType(name));
         }
         return global;
@@ -1088,6 +1096,24 @@ class Compiler
             case NodeType.RepeatUntil:
                 compileRepeat(cast(RepeatUntil)i, s);
                 break;
+            case NodeType.Option:
+                if(isDirectMode)
+                {
+                    throw new CantUseFromDirectMode();
+                }
+                else
+                {
+                    auto option = cast(Option)i;
+                    if (option.argument == "STRICT")
+                    {
+                        isStrictMode = true;
+                    }
+                    else if (option.argument == "DEFINT")
+                    {
+                        isDefint = true;
+                    }
+                }
+                break;
             default:
                 stderr.writeln("Compile:NotImpl ", i.type);
         }
diff --git a/SMILEBASIC/error.d b/SMILEBASIC/error.d
index 42730de..dd36186 100644
--- a/SMILEBASIC/error.d
+++ b/SMILEBASIC/error.d
@@ -80,6 +80,14 @@ class OutOfDATA : SmileBasicError
         super("Out of DATA");
     }
 }
+class UndefinedVariable : SmileBasicError
+{
+    this()
+    {
+        this.errnum = 15;
+        super("Undefined variable");
+    }
+}
 class DuplicateVariable : SmileBasicError
 {
     this()
diff --git a/SMILEBASIC/node.d b/SMILEBASIC/node.d
index 4d49af4..9169a19 100644
--- a/SMILEBASIC/node.d
+++ b/SMILEBASIC/node.d
@@ -42,6 +42,7 @@ enum NodeType
     On,
     Input,
     RepeatUntil,
+    Option,
 }
 abstract class Node
 {
@@ -578,3 +579,14 @@ class RepeatUntil : Statement
         this.statements = statements;
     }
 }
+
+class Option : Statement
+{
+    wstring argument;
+    this(wstring arg, SourceLocation loc)
+    {
+        super.location = loc;
+        this.type = NodeType.Option;
+        argument = arg;
+    }
+}
diff --git a/SMILEBASIC/parser.d b/SMILEBASIC/parser.d
index 391ecac..402f25d 100644
--- a/SMILEBASIC/parser.d
+++ b/SMILEBASIC/parser.d
@@ -847,6 +847,22 @@ class Parser
                             return node;
                         }
                     }
+                    if (name == "OPTION")
+                    {
+                        if (token.type != TokenType.Iden)
+                        {
+                            syntaxError();
+                            return null;
+                        }
+                        auto arg = std.uni.toUpper(token.value.stringValue);
+                        if (arg != "STRICT" && arg != "DEFINT" && arg != "TOOL")
+                        {
+                            syntaxError();
+                            return null;
+                        }
+                        lex.popFront();
+                        return new Option(arg, lex.location);
+                    }
                     //命令呼び出し
                     auto func = new CallFunctionStatement(name, lex.location);
                     node = func;