To provide a thermostat operable at a prescribed set temperature without disturbance of bimetal operation, and to provide an image forming apparatus equipped therewith.

This thermostat is constituted of a base member, an inner lid mounted on the base member, the bimetal held by the inner lid, a cap which is a heat-sensitive face mounted on the base member so as to cover the bimetal, a washer for holding inversion movement of the bimetal between the cap and the bimetal, an openable/closable contact held by the base member, and a guide pin for interlocking the inversion movement of the bimetal with contact opening/ closing operation. The thermostat and the image forming device equipped therewith are characterized by (1) forming a spot for holding the inversion movement of the bimetal of the washer to have a projecting shape so as to cover a joint face between the washer and the inner lid, and by (2) forming the end shape of the bimetal to have a shape bent at angle of 90° or below.