A non-contact power transmission device includes a resonance coil and a resonance capacitor, and includes impedance variable circuits the impedance of which can be changed. In the non-contact power transmission device, a power transmission side controller changes impedance of one of the impedance variable circuits, a power reception side controller changes impedance of the other one of the impedance variable circuits, and output impedance on a power supply side with respect to a power transmission coil unit and input impedance on a load side with respect to the power transmission coil unit are matched.