A semiconductor device includes an N-type semiconductor substrate, an epitaxial layer, a trench structure, a gate, an interlayer dielectric layer, a source, and a drain. The trench structure is disposed at the epitaxial layer. The trench structure includes a plurality of first trenches and one second trench. The plurality of first trenches extend in a first direction and are arranged at intervals in a second direction. The second trench extends in the second direction. The second trench and each of the plurality of first trenches are disposed in a cross manner and communicate with each other. The interlayer dielectric layer covers the gate, and has a contact hole that extends in the second direction. The source is disposed at the interlayer dielectric layer, and is in contact, through the contact hole, with the epitaxial layer.