To provide a plane patched antenna the resonance frequency of which is adjustable, without changing the sizes of a radiation conductor and a ground conductor.

The patched antenna has a radiation conductor 10, a high dielectric constant resin board 14 and a ground conductor 12 formed in one body by injection-forming a high dielectric constant resin. The radiation conductor 10 surface is set to be higher or lower than the resin board surface 14p around it to adjust the resonance frequency. For the injection-forming, a die is used which has a region for setting the radiation conductor. The surface position of this region is adjustable, relative to a surface around this region, in a direction perpendicular to both surfaces.