A power transmission apparatus, which includes a first resonator, for detecting a position of a power reception apparatus, which includes a load and a second resonator, wherein the first resonator includes a first coil, and wherein the second resonator includes a parallel resonance circuit having a second coil and a capacitor (C2p), the power transmission apparatus comprising: an oscillation circuit adapted to oscillate alternating current power at a first frequency which is lower than a resonant frequency (fr) of the second resonator and at a second frequency which is higher than the resonant frequency (fr); and a measuring circuit, characterized in that in operation, the measuring circuit is adapted to: measure inductance values of the first resonator when the first resonator is electromagnetically coupled to the second resonator; measure an inductance value Lin when the oscillation circuit oscillates alternating current power at the first frequency while the second resonator is substantially in the opened state at the first frequency, and to measure an inductance value Lin when the oscillation circuit oscillates alternating current power at the second frequency while the second resonator is substantially in the short-circuiting state at the second frequency; and calculate a coupling coefficient k by using an expression represented by k 2 = 1-Lin /Lin, to detect a relative position of the second resonator with respect to the first resonator on the basis of the coupling coefficient k. an oscillation circuit adapted to oscillate alternating current power at a first frequency which is lower than a resonant frequency (fr) of the second resonator and at a second frequency which is higher than the resonant frequency (fr); and a measuring circuit, characterized in that in operation, the measuring circuit is adapted to: measure inductance values of the first resonator when the first resonator is electromagnetically coupled to the second resonator; measure an inductance value Lin when the oscillation circuit oscillates alternating current power at the first frequency while the second resonator is substantially in the opened state at the first frequency, and to measure an inductance value Lin when the oscillation circuit oscillates alternating current power at the second frequency while the second resonator is substantially in the short-circuiting state at the second frequency; and calculate a coupling coefficient k by using an expression represented by k 2 = 1-Lin /Lin, to detect a relative position of the second resonator with respect to the first resonator on the basis of the coupling coefficient k. measure inductance values of the first resonator when the first resonator is electromagnetically coupled to the second resonator; measure an inductance value Lin when the oscillation circuit oscillates alternating current power at the first frequency while the second resonator is substantially in the opened state at the first frequency, and to measure an inductance value Lin when the oscillation circuit oscillates alternating current power at the second frequency while the second resonator is substantially in the short-circuiting state at the second frequency; and calculate a coupling coefficient k by using an expression represented by k 2 = 1-Lin /Lin, to detect a relative position of the second resonator with respect to the first resonator on the basis of the coupling coefficient k.