In a MOSFET of an LDD structure, a side wall (51) is made conductive and connected to a gate (3) through a resistance (13) thereby to cause hot carriers taken into the side wall (51) to be discharged to a gate (3) through the resistance (13), whereby a channel resistance is prevented from being increased by an effect of carriers accumulated in the side wall (51). As a result, a reliable MOSFET with a short channel can be provided which is not degraded even if it is used for a long time.
