PURPOSE: To eradicate a malfunction and to guarantee a safety operation by inputting an output signal from a rectifying device and a interrupting signal from an interrupting signal generating means and discriminating it to be an operating/actuating input of a switch, when the output signal from the rectifying device is decided to be an alternating signal.

CONSTITUTION: A rectifying circuit 10 consisting of a switch SW, a rectifying device 13, etc., provided in series to an AC power source 1, and an interrupting signal generating means 20 are connected. Also, the subject device is provided with an alternating signal discriminating means 30 for discriminating it to be an operating/actuating input of the switch SW, when an output signal S from the rectifying device 13 and an interrupting signal Sp from the interrupting signal generating means 20 are inputted, and the output signal S from the rectifying signal 13 is decided to be an alternating signal, and when it is discriminated to be the alternating signal, it is handled as a switch input. In such a way, if abnormality or a fault occurs in one of components, the switch input is no generated, therefore, a malfunction is eradicated, and the press operation can be guaranteed safely and surely.