There is provided a semiconductor device in which an influence of a power source noise is suppressed and the number of pins and the area of the semiconductor device are reduced. A power source line for a first internal circuit and a power source line for a second internal circuit are coupled to a common pin terminal. A ground line for the first internal circuit and a ground line for the second internal circuit are coupled to another common pin terminal. A power source noise generated on the power source line for the first internal circuit during an operation of the first internal circuit is absorbed by a P-channel MOS transistor and a capacitor. A power source noise generated on the ground line is absorbed by an N-channel MOS transistor and the capacitor.