To provide a noncontact power transmission device which is equipped with a secondary resonance coil capable of delivering power between itself and a primary resonance coil, by resonating with a resonator provided outside and including the primary resonance coil via an electromagnetic field, and in which the secondary resonance coil is cooled.

The noncontact power transmission device 101 includes a resonator 112, capable of either receiving power from the resonator 221 by resonating with the resonator 221 provided outside via an electromagnetic field or transmitting power to the resonator 221 by resonating with the resonator 221 via the electromagnetic field; and the resonator 221 includes the primary resonance coil 240 and the resonator 112 includes a secondary resonance coil 110 and has a cooler for cooling the secondary resonance coil 110.