A power transmission apparatus, which includes a first resonator, for detecting a position of a power reception apparatus, which includes 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 operate 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 operates 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 operates at the second frequency while the second resonator is substantially in the short-circuiting state at the second frequency; and determine a ratio of the inductance value Lin and the inductance value Lin, to detect a relative position of the second resonator with respect to the first resonator based on the ratio of the inductance value Lin and the inductance value Lin. an oscillation circuit adapted to operate 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 operates 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 operates at the second frequency while the second resonator is substantially in the short-circuiting state at the second frequency; and determine a ratio of the inductance value Lin and the inductance value Lin, to detect a relative position of the second resonator with respect to the first resonator based on the ratio of the inductance value Lin and the inductance value Lin. 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 operates 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 operates at the second frequency while the second resonator is substantially in the short-circuiting state at the second frequency; and determine a ratio of the inductance value Lin and the inductance value Lin, to detect a relative position of the second resonator with respect to the first resonator based on the ratio of the inductance value Lin and the inductance value Lin.