To prevent control software from being imitated or copied outside a game apparatus.

A CPU 11, a memory 1 and an external bus interface circuit 1 for inputting and outputting a control signal of the CPU 11 to the outside are connected to one another by a data bus L1, the above members 11, 12, 19 are stored in the same integrated circuit 1, and the external bus interface circuit 19 inhibits data on the data bus L11 from being read out to the outside of the integrated circuit 1, whereby data processed by the CPU 11 and data written in a memory 12 can not be outputted.