PURPOSE: To improve the deterioration of the side lobe characteristic that is caused by the feeder extending between the mirror surface and the radiation part of a parabolic antenna.

CONSTITUTION: A parabolic antenna have a feeder 3 consisting the 1st and 2nd curved waveguide 4, 5, and etc. And the feeder 4 guides radio wave into radiator part 2 from which radio wave irradiates an antenna mirror surface 1 of the parabolic antenna. Then a metallic matter 6 having a shape almost symmetrical to the feeder 3 is provided opposite to the feeder 3. Thus the radio wave sent from the part 2 is reflected between the feeder 3 and the matter 6. This reflection functions to attenuate the radio wave to reduce the influence to a side lobe. The same effect is also secured when the 1st and 2nd feeder are provided almost symmetrical to each other or a radio wave absorber is provided at the outer circumferential part of the feeder.