To provide a temperature-sensitive pellet type thermal fuse in which fluctuations of operating temperature are suppressed even after storing for a long time in a high-temperature state and an effect due to the passage of time is not caused and which is stable, in order to improve reliability of a temperature-sensitive pellet type thermal fuse.

The temperature-sensitive pellet type thermal fuse has a pair of lead members of a first lead lead-out portion 14 adhered on one-end opening side and a second lead lead-out portion 16 caulking fixed on the other end opening side installed on a metal case housing 12, and a switching member consisting of a temperature-sensitive pellet 10 having PTT as a main material and a spring body is housed in the metal case housing 12. Here, the temperature-sensitive pellet 10 has an operating temperature of 220-235C as an auxiliary material is added to a crystalline thermoplastic resin of polyester system PTT of the main material.