A junction FET having a large gate noise margin is provided. The junction FET comprises an n− layer forming a drift region of the junction FET formed over a main surface of an n+ substrate made of silicon carbide, a p+ layer forming a gate region formed in contact with the n− layer forming the drift region and a gate electrode provided in an upper layer of the n+ substrate. The junction FET further incorporates pn diodes formed over the main surface of the n+ substrate and electrically connecting the p+ layer forming the gate region and the gate electrode.