A power supply control mechanism comprising: a power supply control unit that includes a detection terminal and controls a power supply from a power source to a driving circuit so as to switch an operation mode of a device between a sleep mode and a normal operation mode; a push switch that generates an electronic signal to be applied to the detection terminal only for a fixed time according to operation by a user; and a signal generation unit that operates with a power supplied from the power source under the power supply control of the power supply control unit, and generates a detection signal to be applied to the detection terminal and grasps a voltage applied to the detection terminal, wherein, in the sleep mode, the power supply control unit, upon detecting the operation of the push switch on the basis of the voltage of the detection terminal, switches the operation of the device from the sleep mode to the normal operation mode so as to start the power supply from the power source to the driving circuit and to the signal generation unit for operation, in the normal operation mode, the signal generation unit, upon detecting the operation of the push switch on the basis of the voltage of the detection terminal, stops the output of the detection signal, and the power supply control unit, upon detecting the stoppage of the detection signal on the basis of the voltage applied to the detection terminal, switches the operation mode of the device from the normal operation mode to the sleep mode so as to stop the power supply from the power source to the driving circuit and to the signal generation unit. a power supply control unit that includes a detection terminal and controls a power supply from a power source to a driving circuit so as to switch an operation mode of a device between a sleep mode and a normal operation mode; a push switch that generates an electronic signal to be applied to the detection terminal only for a fixed time according to operation by a user; and a signal generation unit that operates with a power supplied from the power source under the power supply control of the power supply control unit, and generates a detection signal to be applied to the detection terminal and grasps a voltage applied to the detection terminal, wherein, in the sleep mode, the power supply control unit, upon detecting the operation of the push switch on the basis of the voltage of the detection terminal, switches the operation of the device from the sleep mode to the normal operation mode so as to start the power supply from the power source to the driving circuit and to the signal generation unit for operation, in the normal operation mode, the signal generation unit, upon detecting the operation of the push switch on the basis of the voltage of the detection terminal, stops the output of the detection signal, and the power supply control unit, upon detecting the stoppage of the detection signal on the basis of the voltage applied to the detection terminal, switches the operation mode of the device from the normal operation mode to the sleep mode so as to stop the power supply from the power source to the driving circuit and to the signal generation unit.