PURPOSE: To improve the economicity of a firmware loading system by providing an address converter means which converts the addresses of a 1st storage which is transmitted for a processor to carry out an initial program and a loading program into the addresses of the initial program and the loading program stored in a 2nd storage.

CONSTITUTION: A 2nd storage 300 owns an address area different from that of a 1st storage 200. Then the storage 300 stores an updating program 301 in place of a program 201 of the storage 200, an initial program 302 needed for a processor 100 to initialize an information processing system, and a loading program 303 needed for the processor 100 to update the program 201 into the program 301. An address converter means 400 converts the addresses of the storage 200 used by the processor 100 to carry out both programs 302 and 303 into the addresses of these programs 302 and 303 of the storage 300. Thus, the economicity can be improved in a firmware loading system.