IC CARD

PURPOSE:To prevent the unfair forging by providing an area having an address in the control of a memory control means at a non-volatile memory and an area having the special address outside the control and executing the writing through the control program of a memory control means. CONSTITUTION:In a ROM 4, a program, etc., to write the program able to be executed by a microprocessor unit (MPU)6 from an external part into a non-volatile memory 3A are stored besides the program to control the memory space of the non-volatile memory 3A. An address control lower limit address 18 of the memory 3A able to be controlled by the memory control program of the ROM 4 and a control upper limit address 19 are recorded in a special address 17 of the ROM 4. The memory control program of the ROM 4 refers to the special address 17, only the memory space of the range is read and the object of the writing is obtained. Thus, a memory 3B cannot read and rewrite at the program of the ROM 4 and the unfair forging can be prevented.