To provide a wireless tag communication apparatus realizing high sensitivity without reference to the relative positional relation to a wireless tag.

The wireless tag communication apparatus has an antenna 54 which comprises a plurality of antenna elements 18 arranged in designated positional relation and can control the plane of polarization and the directivity of a transmitted signal and a transmission weight control part 36 which controls the plane of polarization and the directivity of the transmitted signal transmitted from the antenna 54, so the plane of polarization and the directivity of the transmitted signal can be adjusted to a wireless tag 14 being the object of communication whatever relative position the wireless tag 14 is disposed at. Namely, provided is the wireless tag communication device 12 realizing high-sensitivity communication irrelevantly to the relative positional relation to the wireless tag 14.