A semiconductor device includes a semiconductor substrate having an element region and a terminal region located around the element region. The terminal region includes multiple guard rings and multiple first diffusion regions. When the semiconductor substrate is viewed in a plan view, one of the first diffusion regions is arranged correspondingly to one of the guard rings, and each of the guard rings is located in corresponding one of the first diffusion regions. A width of each of the first diffusion regions is larger than a width of corresponding one of the guard rings.