A resonance contactless power supply device can include: (i) a converter configured to convert an input power signal to an adjustable DC voltage; (ii) an inverter configured to receive the adjustable DC voltage, and to generate an AC voltage with a leakage inductance resonance frequency; (iii) a first resonance circuit having a transmitting coil, and being configured to receive the AC voltage from the inverter; (iv) a second resonance circuit comprising a receiving coil that is contactlessly coupled to the transmitting coil, where the second resonance circuit is configured to receive electric energy from the transmitting coil; and (v) a control circuit configured to control the adjustable DC voltage according to a phase difference between the AC voltage and an AC current output by the inverter, such that the phase difference is maintained as a predetermined angle.