The present disclosure relates to a resonance-type contactless power supply, an integrated circuit and a constant voltage control method. The resonance-type contactless power supply includes an inverter, a transmitter-side resonant circuit, a receiver-side resonant circuit, a rectifier circuit, and an output capacitance. In this resonance-type contactless power supply, the inverter receives electric energy, which is transferred to the rectifier circuit in a first state and is not transferred to the rectifier circuit in a second state. By switching between the first state and the second state, the resonance-type contactless power supply is controlled to provide a relatively constant voltage, and can be electrically coupled directly to a constant-voltage-type load.