PURPOSE: To vary the direction of a radio linearly polarized wave by providing plural feeding points on a circle of a radiation patch so as to switch a feeder sequentially by a change over switch.

CONSTITUTION: A circular radiation patch 3 is provided on the surface of a dielectric base 1 provided with a metallic ground plate 2 at its rear face while forming a patch antenna sending/receiving a linearly polarized wave. Plural feeding points 4a to 4h are provided on circles concentric to the patch 3 thereupon and feeders 5a to 5h connecting the feeding points 4a to 4h are switched sequentially one by one by a changeover switch to select sequentially a polarized wave vector going to the feeding points 4a to 4h representing the polarized wave direction and the patch antenna varying the direction of the transmitted/ received linearly polarized wave is formed.