To surely and easily detect a foul deed wherein an authentic game program which is provided by a game machine maker is illegally used even by a constitution wherein a CPU and a ROM are separate bodies by irreversibly prohibiting an ex post facto access for genuine/false information which is stored in a genuine/false information memory part.

An identification circuit 10H substantially stops a CPU for one time, and confirms the agreement between a check code which is calculated by a ROM check circuit 10Hh and a program check code of a built-in ROM, and judges that an application program for a game is an authentic program which is fed frown the game maker. In addition, the ROM check circuit 10Hh confirms the agreement between an individual check code which is secretely and peculiarly stored by itself, and the check code of the built-in ROM, and judges whether the authetic program is prepared for other game machines or not. Then, only when all of these conditions are satisfied, the operation of the CPU is allowed.