The present invention discloses an electronic device having a main microcomputer that controls some functions of the electronic device, and a sub microcomputer that executes a process according to an operation input from an external device by using a control program. The sub microcomputer has a first memory that stores plural control programs respectively corresponding to each different specification of the electronic device. The main microcomputer has a second memory that stores specification information to specify the electronic device and sends a selection instruction of the specification to the sub microcomputer based on the specification information stored in the second memory. The sub microcomputer selects the control program corresponding to the specification indicated by the selection instruction from the plural control programs stored in the first memory and then executes a process according to the selected control program.