A patch antenna includes a dielectric body, radiation element, earth conductor and feed member. The dielectric body increases in cross-sectional area from a first end toward a second end thereof. The radiation element is disposed on a surface of the dielectric body, and each side of the radiation element has a length adjusted based on the frequency of a radio wave to be received and the effective permittivity of the dielectric body. The earth conductor is disposed on the bottom surface of the dielectric body. The feed member is electrically connected to the radiation element.