A contactless power transmission device (10) includes a switching unit (32) that switches a power transmission line (EL1, EL2) so that a first power is transmitted through the first line (EL1) when an AC power supply (12) outputs a first AC power and so that a second power is transmitted through a second line (EL2) when the AC power supply (12) outputs a second AC power. An impedance conversion unit (31) is arranged on the second line (EL2) that converts an impedance from an output of the AC power supply (12) to a variable load (22) when the second power is transmitted through the second line (EL2) to approach an impedance from the output of the AC power supply (12) to the variable load (22) when the first power is transmitted through the first line (EL1).
