To provide a connector for wiring such as a bayonet plug, or a receptacle with response improved to generation of heat.

A first and a second cords 211, 212 separating a power source cord 207 are connected to a first or a second heating surface part 216, 217 each made of flat-plate metal. The heating surface parts 216, 217 are in contact with a thermostat main body 213 through a thin-film insulating board 218. Its response to heat is better than, therefore, in the case where an overheated state of a coated wire is detected. Temperatures of blades 201, 202 and a bottom face of a case 203 can also be detected at the heating surface parts 216, 217.