PURPOSE: To accurately measure covering a wide angle radiation pattern of an antenna by mounting an antenna to be tested on a rotary base pedestal having a horizontal axis of rotation and an axis of elevation which is in a plane involving the antenna to be tested and an opposed antenna.

CONSTITUTION: A rotary base pedestal 2 on which an antenna to be tested 1 is mounted has a horizontal aixs 4 of rotation and an axis 10 of rotation of elevation which is in a plane involving the antinna to be tested 1 and an opposed antenna 3. The horizontal axis 4 of rotation is provided above the axis 10 of rotation of elevation. The antenna to be tested 1 is rotated around the horizontal axis 1 of rotation as the antenna 1 is inclined at a predetermined angle with respect to the axis 10 of rotation of elevation, so that a beam 9 from the antenna 1 is moved in a plane 5 of rotation which makes a predetermined angle to a horizontal plane 6. Therefore, the advancing direction in which a reflected wave 8 from an obstacle 7 on the grond never agrees with the direction on which the beam 9 advances. As a result, a radiation pattern of the antenna to be tested is not affected by the reflected wave 8. Thus, even a wide angle radiation pattern of a low level of an antenna can be accurately measured.