On the other hand, in a case where a request to stop displaying the two-dimensional code has not been provided, the CPU 101 determines in S507 whether a predetermined time period (for example, 20 seconds) has elapsed. In a case where the predetermined time period has elapsed, the processing proceeds to S508. In S508, the CPU 101 turns off the screen of the display device 20, so that the screen enters into the sleep mode, and the CPU 101 ends the series of processes. In a case where the key group 21 is pressed and the screen returns from the sleep mode, the CPU 101 may display the previously-displayed screen on the display device 20 or may display the menu screen on the display device 20. In such a form in which the previously-displayed screen is to be displayed, the CPU 101 continues displaying the screen of the two-dimensional code at the second refresh rate R2 for displaying a code in the case where the screen returns from the sleep mode after entering into the sleep mode in S508. In such a form in which the menu screen is to be displayed in the case where the screen returns from the sleep mode, the CPU 101 displays the menu screen on the display device 20 at the first refresh rate R1 of the normal mode in the case where the screen returns from the sleep mode after entering into the sleep mode in S508.