In an electronic device for implementing various functions using a DSP, the functionality can be updated as required. The electronic device is provided with a DSP and a flash memory for storing a program executed by the DSP. A program for implementing a new function implements both an old function and the new function, and for implementing a function corresponding to a version flag that has been set in version flags. When the program in the flash memory is updated to a program for implementing the new function, the program for implementing a new function is loaded into the flash memory, and a version flag corresponding to the new function is set in the version flags.