Wireless power transmission device

A power transmission device includes: a power transmission antenna including element antennas to radiate a radio wave and element modules each provided for a predetermine number of element antennas and including a phase shifter to change a phase of a transmission signal radiated as the radio wave and an amplifier to amplify the transmission signal; and an REV method phase controller to change the phase of the transmission signal by a phase shift amount obtained by adding an operation phase shift amount for executing the REV method and a direction change phase shift amount for changing a transmission direction, for an operating phase shifter being part of the phase shifters, such that operation of changing the phase shift amount of the operating phase shifters is repeated while changing the operating phase shifters in a state in which at least some element antennas radiate the radio wave.