To surely prevent an electric shock accident by cutting off the supply of commercial power and preventing the occurrence of leakage in case that the earth condition of a washing machine is not good.

In case that the power switches 40 and 41 of a washing machine are on by the relay circuit 56 as a power supply control means and that the closing condition of the circuit between the resistor 51 being a first element and the step-up transformer 53 being a third element or between the resistor 52 being a second element and the step-up transformer 53 being a third element is good, the power supply is performed by the on of the relay contacts 57 and 58 being break and connection means. Moreover, in case that the closing condition of the circuit between the resistor 51 and the step-up transformer 53 or between the resistor 52 and the step-up transformer 53 is abnormal, the power supply is cut off by the off of the relay contacts 57 and 58.