PURPOSE: To provide a cheap structure with good assembly characteristic by reducing the number of parts in the internal structure of a thermometer switch.

CONSTITUTION: A transmission rod 5 formed from an insulating material is installed between a movable contact plate 3 and a movable contact plate 4 opposed to each other on the movable contact plate 3 on one side, in a thermometer switch 1. A jumping type bimetal 6 is installed between the tip of the transmission rod 5 and the movable contact plate 4 on the other side. Namely the transmission rod 5 formed from the insulating material is installed between the opposed contact plates on the movable contact plate on one side and the bimetal is installed between the tip of the transmission rod and the movable contact plate on the other side so that the number of parts can be reduced and a cheap structure with good assembly characteristic can be provided.