PURPOSE: To prevent a rush current normally used from being cut off while surely cutting off currents in abnormalities.

CONSTITUTION: One end portion of a conductive, columnar fuse main body 2 having a lead wire 4b connected thereto is held on a socket portion 1 having a lead wire 4a connected thereto. The socket portion 1 comprises two conductors of different coefficients of thermal expansion stacked one atop the other along the radial direction of the fuse main body 2 in such a manner that the outside conductor is greater in coefficient of thermal expansion than the inside one. A plate spring 3 for constantly pressing the fuse main body 2 so that the main body 2 is pulled out of the socket portion 1 is provided at the other end face of the fuse main body 2. When an excess current flows between the lead wires 4a, 4b, the socket portion 1 is heated and expanded because of the difference in coefficient of thermal expansion between the conductors. Therefore, the fuse main body 2 is pulled out of the socket main body 1 by the plate spring 3 so that the current is cut off.