POWER TRANSMISSION DEVICE

A power transmission device includes: a coil that performs power transmission or power reception in a wireless manner; a power supply device that is connected to the coil and applies a voltage to the coil; and a control device that controls the power supply device. When detecting an electric leakage of the power transmission device, the control device controls the power supply device to maintain both output terminals of the power supply device at the same potential different from a ground potential, and detects the electric leakage based on electrical characteristics of the power transmission device at this time.