A fuse includes: a first connecting terminal to be connected to a power source; a second connecting terminal to be connected to a load; a third connecting terminal to be connected to a relay control circuit; a fuse element having one end to be connected to the first connecting terminal; and a semiconductor relay directly mounted on the second connecting terminal. The semiconductor relay is a relay circuit switching between conducting and non-conducting states of a connection between its own drain and source electrodes, according to control signals inputted to the own gate electrode. The drain, source and gate electrodes are electrically connected to the other end of the fuse element, the second connecting terminal and the third connecting terminal, respectively. The first to third connecting terminals, the fuse element and the semiconductor relay are formed in an integral structure with a mold resin sealing portion.