To detect, surely and easily in a low cost, abnormal heat generation including a past career, by forming a laminate by laminating a thermal shrinkage polymer film on a metal thin plate.

This abnormal heat generation detecting element 10 comprises a laminate 13 formed by laminating a thermal shrinkage polymer film 11 on a metal thin plate 12. The thermal shrinkage polymer used for the film 11 is a polymer having phase transition generated at an inherent temperature, for example, a thermoplastic resin, such as polyethylene or the like, is used. In a manufacturing method of the abnormal heat generation detecting element 10, a thermal shrinkage polymer having a phase transition temperature at the temperature required to be detected is selected as an abnormal heating element, and the thermal shrinkage polymer is heated up to a temperature higher than the phase transition temperature, and thereafter rolled into a film shape and molded. Then, the polymer is cooled at a temperature lower than the phase transition temperature, in the state where the shape of the film 11 is maintained.