Provided is an antenna apparatus which is capable of improving a gain in a specific direction, reducing an unnecessary gain in an angle range, and reducing its height. A radome 220 is formed such that a central portion positioned above a patch array antenna 130 is formed in different shapes in an outer wall and an inner wall. The central portion of the outer wall of the radome 220 is formed in a flat shape, and thus the height of the radome 120 is reduced. On the other hand, the center portion of the inner wall of the radome 220 is formed such that a radome thickness at a position of the radome 220 in directions in which an angle θ is about −45° and about +45° when viewed from the center of the patch array antenna 130 changes stepwise.