A semiconductor device has transistors formed on a substrate and including first and second impurity regions of a first conductivity type, a guard ring of a second conductivity type formed on the substrate and surrounding the transistors in a plan view, a wiring formed on and electrically connected to the guard ring, and a ground wiring formed on the wiring and electrically connected to the wiring and the second impurity region. In a plan view, the transistor includes a first part having a distance that is a first distance from the guard ring, and a second part having a distance that is a second distance shorter than the first distance from the guard ring. In a plan view, the first part is located at a position separated from the ground wiring, and the second part is located at a position overlapping the ground wiring.