As a power feed route in a semiconductor chip, a power feed route which reduces antiresonance impedance in the frequency range of tens of MHz is to be realized thereby to suppress power noise in a semiconductor device. By inserting structures which raise the resistance in the medium frequency band into parts where the resistance is intrinsically high, such as power wiring in a semiconductor package and capacitor interconnecting electrode parts, the antiresonance impedance in the medium frequency band can be effectively reduced while keeping the impedance low at the low frequency.