Abstract: A semiconductor device that makes isolation circuits unnecessary and that also resolves the problem of through-current flowing during power supply shutdown transitions and during power supply recovery and that even flows between the regions during power shutdown. A semiconductor device of the present invention including a first power supply line, and a second power supply line coupled to a first power supply line by way of a first switch, a macro cell containing a macro cell core coupled to the second power supply line, and a third power supply line coupled by way of a second switch to a first power supply line, and a circuit block coupled to the third power supply line and also coupled to at least either the macro cell core input or output; and the second power supply line is coupled to the third power supply line.