A circuit board includes: a semiconductor substrate including a first surface and a second surface located at an opposite side from the first surface; a circuit provided at a first surface side; a first external electrode provided at a second surface side; a heater provided at the second surface side; and a plurality of through electrodes penetrating the first surface and the second surface and electrically coupling the circuit and the first external electrode or the heater. The heater and the first external electrode do not overlap each other in a plan view.