A semiconductor device which can avoid increase of a conduction loss of an IGBT, secure a low noise characteristic and also reduce a switch loss. The switching device is of a trench gate type, in which a drift n− layer 110 is exposed to its main surface to a floating p layer 126 and to trench gates. In other words, the floating p layer 126 is provided within the drift n− layer 110 to be spaced from the trench gates.