A semiconductor device of the present invention comprises: a semiconductor substrate of a first conductive type; a gate electrode formed on the semiconductor substrate; a first semiconductor region of a second conductive type different from the first conductive type, the first semiconductor region being formed on the semiconductor substrate in one of both side regions of the gate electrode so as to be adjacent to the gate electrode; a second semiconductor region of the second conductive type formed on the semiconductor substrate in the other region of the both side regions of the gate electrode so as to be adjacent to the gate electrode; a third semiconductor region of the second conductive type formed in the one region so as to be isolated from the first semiconductor region and to be spaced from the second semiconductor region by a greater distance than that between the first and third semiconductor regions; a connecting portion for connecting the first semiconductor region to the third semiconductor region, the connecting portion having a higher resistance than those of the first and third semiconductor regions; a first electrode formed so as to be electrically connected to the third semiconductor region; and a second electrode formed so as to be electrically connected to the second semiconductor region. Thus, it is possible to prevent the element characteristics from deteriorating even if a surge voltage is applied and to decrease the element size.