PURPOSE: To obtain higher accuracy in assembling both parts as a pair via welding by forming a recess on one of the parts to be welded and carrying out welding with the other part engaged with the recess.

CONSTITUTION: A recess 6 is formed at positions to be welded to a terminal pin 11 on one side of a contact point terminal plate 4 continuous to two pairs of fixed contact point plates 41 and 42. In this welding work, each terminal pin 11 is inserted in a plurality of recesses 6 so formed as to correspond to each contact point plate 41 and 42, and then welded. In this case, only one of the recesses 6 is made to have a wedge shape cross section, and other recesses 6 are groove type wider than the diameter of the pin 11, thereby allowing the pin 11 to move slightly in the recess 6. Also, a card 25 is welded to both edges of an armature 23 in such a way that a groove type recess 61 is formed on both edges of the armature 23 and a projection 52 is formed on the card 25 for engagement with the recess 61. And welding is carried out with the projection 52 coupled to the recess 61.