To provide an alloy type thermal fuse of high reliability whereby mechanical damage by thermal stresses can be prevented even if it is exposed to severe temp. cycles.

An alloy type thermal fuse 10 is structured so that a thermo- sensitive soluble material 14 consisting of a low-melting point alloy is accommodated in a cylindrical insulation case 12 and the opening of this case 12 is sealed with a resin molding 11, wherein the resin molding 11 holds the edge 12a of the case opening pinchedly by the inside surface 12ai and outside surface 12ao and is attached fast to the opening.