A phased array antenna apparatus includes: an antenna array portion having a plurality of antenna elements (2) disposed at equal intervals, and a plurality of phase shifters (3), each phase shifter being connected between the adjacent antenna elements and changing a phase of a transmission signal; a phase shifter control portion (4) controlling each phase shift quantity of the plurality of phase shifters (3); and a power feed path switching portion (5) for switching a power feed path from an external apparatus (6) to the antenna array portion to one of a path from one end of the antenna array portion and a path from the other end of the antenna array portion, and causing the control by the phase shifter control portion (4) to correspond to the switching.