A semiconductor device includes: a first power line to supply a first voltage to a plurality of internal circuits; a second power line to supply the first voltage to the plurality of internal circuits; a first switch provided between said first power line and each of the plurality of internal circuits; a second switch provided between said second power line and each of the plurality of internal circuits; and a control circuit to control the first switch of a second internal circuit included in the plurality of the internal circuits based on the amounts of noise and voltage drop at power-on in a first circuit included in the plurality of internal circuits.