PURPOSE: To let good spot welding be effected through application of pressing force corresponding to the members to be welded between electrode tips by operating a handle to turn a moving body by way of an operating rod and suitably adjusting the spring provided to the operating rod.

CONSTITUTION: When a handle 10 is turned counterclockwise, an operating rod 13 is moved leftward and a moving body 5 turns counterclockwise about an axis 4, by which electrode tips 3, 8 are spaced. In this state, the materials to be welded are disposed between the tips 3, 8, after which the handle 10 is turned clockwise by gripping the portion between the body 1 and handle 10. Thereby, the materials to be welded are held between the tips 3, 8. When the handle 10 is further turned clockwise, the pressing force corresponding to the deviating force of the spring 15 is applied between the tips 3, 8, i.e., the materials to be welded. At this same instant, a microswitch 18 is turned ON, by which a power source unit is started and the welding current flows between the tips 3, 8 by way of conductors 2, 7, whereby the materials to be welded are spot-welded.