In a lateral-type power MOSFET, high breakdown voltage is achieved with suppressing to increase a cell pitch, and a feedback capacity and an ON resistance are decreased. An n− type silicon region having a high resistance to be a region of maintaining a breakdown voltage is vertically provided with respect to a main surface of an n+ type silicon substrate, and the n− type silicon region having the high resistance is connected to the n+ type silicon substrate. Also, a conductive substance is filled through an insulating substance inside a trench formed to reach the n+ type silicon substrate from the main surface of the n+ type silicon substrate so as to contact with the n− type silicon region having the high resistance, and the conductive substance is electrically connected to a source electrode.