A semiconductor device includes: first and second circuit cell arrays extending in first direction; first and second power supply lines each extending in first direction and arranged over first circuit cell array, first power supply line being supplied with first power source voltage; third power supply line extending in first direction separately from second power supply line, arranged over second circuit cell array, and supplied with second power source voltage; first transistor coupled between second and third power supply lines; and first circuit arranged on first circuit cell array and operating on first and second power source voltages supplied from first and second power supply lines, respectively.