<p>An offset parabola antenna comprises an elliptical parabolic reflector the mirror surface of which has a shape partially cut out from a paraboloid, a primary radiator, and a supporting arm for supporting the primary radiator and fixing the primary radiator to the focal point of the parabolic reflector. The primary radiator is fixed to the supporting arm such that the central axis of a beam where the reception power is maximized in the directional range is directed toward the substantially central position between the central point of an aperture which is the mirror surface position of the parabolic reflector indicated by an axis passing through the center of the aperture, when the parabolic reflector is viewed from the direction from which a radio wave collected at the focal point of the parabolic reflector arrives, and the central point of an aperture angle which is the mirror surface position of the parabolic reflector indicated by a line dividing the aperture angle made by two lines connecting the opposite ends of the parabolic reflector in the direction of long diameter and the focal point of the parabolic reflector equally into two.</p>
