Calibration is performed such that phase references of element antennas match, without radiating radio waves from all element antennas at the same time. A plurality of element antennas are divided into element antenna groups, and operating element antenna sets, each including at least two element antenna groups including a measured element antenna group, are set to an operating state in order by a phase adjustment controller. The phase adjustment controller includes: an element-electric-field calculation circuit that uses a plurality of received power levels of radio waves radiated with different phases by changing the phases of element antennas and that calculates in-set phase differences, in an operating element antenna set, among element electric field vectors generated by the element antennas the phases of which are changed; and a phase-difference calculator that uses element electric field vectors of the element antennas for which the element electric field vectors are calculated by using a plurality of different operating element antenna sets and that calculates phase differences among the element electric field vectors of the element antennas included in the different operating element antenna sets.