<p>A computer device (2) is connected to a USBI/F61 of a scanner (3) through a USB cable (K1). In this case, the computer device (2) is given an access function to a normal storage area (40) of a FLASH-ROM (34) based on the mass storage class specification by a USB mass storage (62). A CPU (111) of the computer device (2) reads an executable file (200) of an application program stored in an application program storage area (41) to which part of the normal storage area (40) of the FLASH-ROM (34) is allocated. Further, the CPU (111) expands the application program in a RAM (112) according to the executable file (200) to start the application program.</p>
