Provided a practical planar antenna device which has antenna elements facing each other, in which electrical power is fed between the antenna elements. The first feeding point is provided near an end of the first antenna element, which faces the opposite antenna element. The second feeding point is provided near an outer end of the second antenna element, by providing a second slit longer than the distance from the end of the second antenna element to its center. Since the feeding points are provided at the same level, the same electric field is excited in the two antenna elements in phase. The planar antenna device, to which electrical power is fed from the facing sides of the pair of opposite antenna elements, saves a bend conventionally required in a feed line, thereby allowing a wiring area to be smaller than in the conventional method.