To provide an alloy-type thermal fuse operable at a high rating, for instance, an alternating current rating of 250 V/15 A under guarantee of overload characteristics, while keeping the basic performance as a thermal fuse, such as aging resistance, and which is capable of satisfactorily ensuring breakdown voltage characteristic and insulation characteristics, after operation, and to provide an alloy-type thermal fuse capable of properly attaining these objectives, even when an eutectic alloy is used for a low-melting-point fusible alloy piece, or an alloy containing Bi and high in a specific resistance value is used.

On a flux coating layer 3a of a flux-coated low-melting-point fusible alloy piece, a coating layer 30 of an organic acid which can be converted into an anhydride by a heating dehydration reaction and has a melting point below that of the low-melting-point fusible alloy piece is formed.