Provided is a semiconductor device which can reduce on-resistance by improving hole mobility of a channel region. A trench gate type MOSFET (semiconductor device) is provided with a p+-type silicon substrate whose crystal plane of a main surface is a (110) plane; an epitaxial layer formed on the silicon substrate; a trench, which is formed on the epitaxial layer and includes a side wall parallel to the thickness direction (Z direction) of the silicon substrate; a gate electrode formed inside the trench through a gate dielectric film; an n-type channel region formed along the side wall of the trench; and a p+-type source region and a p−-type drain region which are formed to sandwich the channel region in the thickness direction (Z direction) of the silicon substrate. The trench is formed to have the crystal plane of the side wall as a (110) plane.