PURPOSE: To simultaneously simply mount an overheat detection element at the time when ends of both conductors are connected to each other by overlapping a plurality of low voltage conductors on the mounting piece of an L-shaped thermal conduction plate, connecting one end of a shape memory alloy to a heat exchanger piece, coupling a needle connected to the other end thereof to a variable resistance slider, introducing one end of a resistance and a slider contact out of a case.

CONSTITUTION: The connection part of two low voltage conductors 22 is overlapped on the mounting piece 25 of an L-shaped thermal conduction plate 23, they are tightened by screws 26, one end of a coil-like two-directional shape memory alloy 29 is connected to a heat exchanger piece 28, a movable piece 32 connected to the other end of the alloy 29 is coupled to a slider 35 of a variable resistance 34, and one end of the resistance 34 and a contact of the slider 35 are introduced out of a case 30 as a control terminal. Thereby an overheat detection element 37 is mounted simultaneously at the time when ends of both the conductors 22 are connected to each other, and mounting work is simple. In addition, design and manufacture are not needed every time sizes of the conductors 22 and correlative pitches are different.