To provide a high voltage resistant vertical MOSFET which, even if it is a wide bandgap semiconductor vertical MOSFET, features low on-resistance and high reliability.

There is provided a MOSFET, composed of a wide bandgap semiconductor and having an active part and a voltage resistant structure part disposed on the periphery thereof, which comprises an n^- drift layer 3 and a p base layer 4 on one side of an n⁺ semiconductor substrate 1 and an n⁺ source layer 5 placed inside the active part in that order. The MOSFET further comprises a trench 100 which, in the active part, extends from the surface of the n⁺ source layer 5 to reach the n^- drift layer 3, and, in the voltage resistant structure part, extends from the p base layer 4 on the outermost surface to reach the n^- drift layer 3, a p-type channel formation layer 6 which covers the side wall of the trench, and a gate electrode which fills the trench including the surface of the p-type channel formation layer. A gate electrode 8 inside the voltage resistant structure part is composed to be in a potentially floating state, while a gate electrode 8 on the outermost periphery is conductively connected to an n⁺ stopper region 16.