The invention relates to an alloy type thermal fuse and a wire member for a thermal fuse element, and provides an alloy type thermal fuse in which a fuse element does not contain a harmful metal, the operating temperature is about 150 C., the dispersion of the operating temperature can be sufficiently suppressed, and the operation stability to a heat cycle can be satisfactorily assured. The thermal fuse has an alloy composition of 30 to 70% Sn, 0.3 to 20% Sb, and a balance Bi.