To make a beam scanning angle to be wide in an array antenna device containing sub-arrays formed of array transmitters/receivers of plural elements 1.

When only an array (a) formed of one element one array transmitters/receivers 2 is operated, a satisfactory antenna gain characteristic can be obtained in a range exceeding a prescribed beam scanning angle with the angle as a boundary compared to a case when a sub-array (b) is also operated. Thus, a device can be used in a wider beam scanning range by permitting a control circuit 9 to switch-control the sub-array (b) formed of plural elements one array transmitters/receivers 3 to be turned off in the range exceeding the beam scanning angle .