A power receiving circuit, a power transmitting circuit, an apparatus, and a feed system are disclosed. The power receiving circuit receives power in a noncontact manner, and includes an LC parallel resonant circuit and a reactance element that is electrically connected in series to the LC parallel resonant circuit. The reactive element may be a capacitive or inductive element. In effect, a coil or capacitor in the LC parallel resonant circuit and the reactance element define another LC resonant circuit, namely, an LC series resonant circuit. The power transmitting circuit transmits power in a noncontact manner, and in one example, may also include a similar configuration.