An engine processor program, stored in a non-volatile storage region 37 of a storage section 35 connected to a host processor 31 of a host section 30, for execution in an engine processor 41 of an engine section 40, is transmitted from the host section 30 to the engine section 40. The engine processor program received by the engine section 40 is stored in a volatile storage section 42 connected to an engine processor 51. Then, the host section 30 notifies an execution instruction for a specified program, among the engine processor programs stored in the storage section 42, to the engine section 40 and causes execution on the engine processor 41. As a result, even in a structure provided, the engine section 40 does not need a large capacity non-volatile storage region, thereby configuring a compact mobile communication terminal.