A semiconductor device includes a first circuit, a second circuit, a first power supply line, a second power supply line coupled to the first circuit, a third power supply line, a fourth power supply line coupled to the second circuit, a first switch circuit including a first switch transistor and a well tap, the first switch transistor including one source or drain end coupled to the first power supply line and another source or drain end coupled to the second power supply line, the well tap being electrically coupled to the second power supply line, and a second switch circuit including a second switch transistor including one source or drain end coupled to the third power supply line and another source or drain end coupled to the fourth power supply line, the second switch circuit including no well tap electrically coupled to the fourth power supply line.