Integrated circuit device includes: a wiring; a clock signal output circuit including a ring oscillator; an internal circuit; an internal power supply generation circuit for supplying an electric power to the clock signal output circuit and to the internal circuit on the basis of a power supplied from an external circuit; and a capacitor connection terminal. The internal power supply generation circuit supplies the electric power to the ring oscillator through the wiring connecting between the internal power supply generation circuit and the capacitor connection terminal. The internal power supply generation circuit supplies the electric power to the internal circuit through the wiring connecting to the capacitor connection terminal.