A patch antenna includes a power feeding conductor pattern formed in a dielectric layer, a ground conductor pattern formed on the dielectric layer, a first parasitic conductor pattern and a second parasitic conductor pattern formed in/on the dielectric layer and is not set to have a ground potential. The first parasitic conductor pattern, the power feeding conductor pattern, the second parasitic conductor pattern, and the ground conductor pattern are arranged in this order in a cross section and overlap each other in a plan view. A resonant frequency f1 defined by an opposite-phase mode current flowing through the first parasitic conductor pattern is higher than a resonant frequency f2 defined by an in-phase mode current flowing through the power feeding conductor pattern, and a resonant frequency f3 defined by an opposite-phase mode current flowing through the second parasitic conductor pattern is lower than the resonant frequency f2.