A contactless power transfer apparatus comprising: a power transmission coil; a primary side capacitor connected to the power transmission coil in series or parallel; a power reception coil opposing the power transmission coil through a gap; and a secondary side resonant capacitor connected to the power reception coil in parallel, wherein the contactless power transfer apparatus is configured to supply power from the power transmission coil to the power reception coil; and the power transmission coil and the power reception coil include: a rectangular or H-shaped core having magnetic pole portions at both ends; and a wire wound around a core part between the magnetic pole portions, a specification of a power source frequency of the power transmission coil and a specification of a resonance frequency of the power reception coil are equal to each other, the contactless power transfer apparatus being characterized in that at least one of a specification of an electrical power and a specification of a gap length of the power transmission coil is different from corresponding specification of the power reception coil, when the specification of the electrical power of the power transmission coil and the specification of the electrical power of the power reception coil differ from each other, the contactless power transfer apparatus is configured to supply power from the power transmission coil to the power reception coil by using the smaller one of the electrical power of the power transmission coil and the electrical power of the power reception coil as a maximum electrical power capable of being supplied, and when the specification of the gap length of the power transmission coil and the specification of the gap length of the power reception coil differ from each other, the contactless power transfer apparatus is configured to supply power by having the power transmission coil and the power reception coil opposing each other through the gap length, which is the specification of the power transmission coil. a power transmission coil; a primary side capacitor connected to the power transmission coil in series or parallel; a power reception coil opposing the power transmission coil through a gap; and a secondary side resonant capacitor connected to the power reception coil in parallel, wherein the contactless power transfer apparatus is configured to supply power from the power transmission coil to the power reception coil; and the power transmission coil and the power reception coil include: a rectangular or H-shaped core having magnetic pole portions at both ends; and a wire wound around a core part between the magnetic pole portions, a rectangular or H-shaped core having magnetic pole portions at both ends; and a wire wound around a core part between the magnetic pole portions, a specification of a power source frequency of the power transmission coil and a specification of a resonance frequency of the power reception coil are equal to each other, the contactless power transfer apparatus being characterized in that at least one of a specification of an electrical power and a specification of a gap length of the power transmission coil is different from corresponding specification of the power reception coil, when the specification of the electrical power of the power transmission coil and the specification of the electrical power of the power reception coil differ from each other, the contactless power transfer apparatus is configured to supply power from the power transmission coil to the power reception coil by using the smaller one of the electrical power of the power transmission coil and the electrical power of the power reception coil as a maximum electrical power capable of being supplied, and when the specification of the gap length of the power transmission coil and the specification of the gap length of the power reception coil differ from each other, the contactless power transfer apparatus is configured to supply power by having the power transmission coil and the power reception coil opposing each other through the gap length, which is the specification of the power transmission coil.