Thermal cut-off fuse

A thermal cut-off fuse for breaking electric continuity between first and second lead wires at a prescribed temperature, which comprises a housing, an electrically conductive contact means contained movably within the hollow space of said housing from the first to the second position, allowed while at the said first position to remain in contact with first and second terminal portions electrically connected within said housing respectively with said first and second lead wires and, while at the second position, to be separated from at least one of the two terminal portions, and a temperature-sensitive member sealed in a space within the housing on the side of the first position of said contact means, with the surface of said member opposed to the contact means, said member being adapted to remain solid under normal conditions and at the prescribed temperature being adapted to melt and undergo voluminal expansion, whereby the melting and voluminal expansion of the temperature-sensitive member at said prescribed temperature causes said surface of the member opposed to the contact means to be moved toward the contact means until the contact means is brought to the second position and the electric continuity between the first and second lead wires is broken.