To provide an antenna assembly and an antenna unit exhibiting stabilized characteristics regardless of an installation place such as on a front glass or a dashboard.

When the antenna assembly 1 is installed on the front glass, only an antenna body 2 is installed closely to the front glass. When the antenna assembly 1 is installed on other than the front glass, e.g. on the dashboard, the antenna body 2 is used while attaching a dielectric board 3 for impedance matching. The antenna body 2 is equipped with a patch antenna 11 and a ground board 12 wherein the patch antenna 11 and the front glass or the dielectric board 3 for impedance matching are arranged closely to each other at a predetermined interval.