A semiconductor device includes: a first domain including a first high power source line, a first low power source line, and a first power clamp circuit; a second domain including a second high power source line, a second low power source line, and a second power clamp circuit; a third power clamp circuit provided between the second high power source line and the first low power source line; a first relay circuit that receives a signal from the first domain and outputs the signal to the second domain; and a second relay circuit that receives a signal from the second domain and outputs the signal to the first domain, wherein the first relay circuit and the second relay circuit have a circuit portion that is connected to the second high power source line and the first low power source line.