A thermal fuse includes a first insulation film having a pair of metal terminals mounted thereto, a fusible alloy located over the first insulation film and connected between respective ends of the metal terminals, a second insulation film provided over the fusible alloy and bonded to the first insulation film as to provide a space between the first and second insulation films. The fusible alloy includes an Sn—Bi—In alloy containing 20 to 39.5 wt. % of tin, 11.5 to 31 wt. % of bismuth, and 49 to 68.5 wt. % of indium. The fusible alloy does not release lead or cadmium even after being disposed of since it contains no lead and no cadmium.