FIG. 10A is a flow chart showing a bank note scanning control routine with further reference to FIG. 9A. When scanning of the bank note M is started (Step S1), the power switch 96 is first turned on (Step S2) and accordingly the CPU 80 calls the program stored in the ROM 82 to start this program, thereby clearing various counters, registers, flags, etc., i.e. performing a so-called initialization.