A thermistor layer of the present invention is configured to be disposed in an electrical current path. The thermistor layer comprises a thermosensitive particle, a plurality of electro-conductive particles covering a surface of the thermosensitive particle, and a binder adhering the electro-conductive particles, the electro-conductive particles form an electro-conductive network, at least the surface of the thermosensitive particle is made of a thermoplastic resin, the thermoplastic resin softens at a temperature lower than a temperature at which the binder softens, and the thermistor layer is provided to become highly resistive due to softening and deformation of the thermoplastic resin.