A semiconductor device having an electric fuse structure which receives an electric current to permit the electric fuse to be cut without damaging portions around the fuse. The electric fuse can be electrically connected between an electronic circuit and a redundant circuit as a spare of the electronic circuit. After these circuits are sealed with a resin, the fuse can be cut by receiving the electric current from the outside. The electric fuse is formed in a fine layer, and is made of a main wiring and a barrier film. The linear expansion coefficient of each of the main wiring and the barrier film is larger than that of each of the insulator layers. The melting point of each of the main wiring and the barrier film is lower than that of each of the insulator layers.