An antenna comprises a ground plate which is planar; a first power feed element which is disposed separately from the ground plate by a prescribed distance and which is formed in a prescribed shape; a first parasitic element which is planar and which is formed in a prescribed shape; a first shortcircuit part which electrically connects the first parasitic element and the ground plate; and a power feed part which is electrically connected with the first power feed element, wherein the first power feed element and the first parasitic element are disposed in parallel in part with each other, and the first power feed element and the first parasitic element have multiple resonances by electro magnetic coupling.