A semiconductor device includes a first area including a logic circuit, a second area including a functional circuit, a first power line, a second power line that supplies a power to the logic circuit and the functional circuit, and a first power switch circuit connected to the first power line and the second power line, wherein the first power switch circuit includes a first transistor larger than a transistor provided in the logic circuit and being connected to the first power line and the second power line, an end cap provided in an area next to the functional circuit, and a second transistor provided between the end cap and an area including the first transistor, the second transistor being of a same size as the transistor provided in the logic circuit and being connected to the first power line and the second power line.