PURPOSE: To make it unnecessary to stop electricity application to polish and clean a contact face in order to prevent electric connection failure or fusion due to the compounds produced in the contact face in the case opening and closing operation is not carried out for a long duration.

CONSTITUTION: A fixed contactor 1 is fixed in a fixing part base while a fixed contactor base 1b being set between a first shape memory alloy 3 and a second shape memory alloy 4. Regarding an electric circuit between the fixed part base 6 and a finger 1a, the first shape memory alloy 3 and the second shape memory alloy 4 compose a series circuit and together with them, a flexible conductor 4 compose a parallel circuit and a part of the current of supplied electricity runs in the first shape memory alloy 3 and the second shape memory alloy 4 to the finger 1a from the fixed base 6. At that time, based on the degree of the increase or decrease of the electricity supply, the first shape memory alloy 1 and the second shape memory alloy 4 are deformed due to their temperature fluctuates over and below the shape memory temperature and following that, the fixed contactor moves up and down.