A wireless power feed system 1 is provided with a power-receiving circuit 6 and a power transmission circuit 3. The power transmission circuit 3 has a power transmission resonance circuit 38 that includes an inductor of self inductance L1 and a capacitor of capacity C1. The power-receiving circuit 6 has a power-receiving resonance circuit 61 that includes an inductor of self inductance L2 and a capacitor of capacity C2. By being driven at a drive frequency ω, the power transmission resonance circuit 38 transmits power from the power transmission circuit 3 to the power-receiving circuit 6. The absolute value of the reactance X1 of the power transmission resonance circuit 38 determined by L1, C1, and ω is set so as to be greater than a first threshold value Th1 (Th1 ≥ 0), and the reactance X2 of the power-receiving resonance circuit 61 determined by L2, C2, and ω is set so as to be 0.