To provide a thermally actuated switch which can mechanically hold contact state after actuation, whereas holding action can be released or prevented during production.

The thermally actuated switch comprises a long thin case 10 equipped with a contact composed of a moving contact 12 and a fixed contact 11, an external connecting terminal 13 connected to the contact, and a bimetal 14 which flips to move the moving contact 12 when temperature goes above a preset temperature. The case 10 is equipped with a latch component 15 which is placed at an end of longitudinal axis and moves freely in the longitudinal direction. The latch component 15 is composed of a conduction blockade 15g which interrupts between the moving contact 12 and the fixed contact 11, and blocks conduction between them when the bimetal 14 flips and a latch mechanism 15f for preventing or releasing the interruption of the conduction blockade 15g.