In an antenna, an antenna element interval is reduced without depending on an interval between converters, to widen the range of a phase folding angle to widen a detection angle range. The antenna includes a first antenna element including a feeder line extending from a first converter and a plurality of radiating elements. A second antenna element includes a feeder line extending from a second converter aligned together with the first converter and a plurality of radiating elements. The first and second antenna elements respectively include, at partial line portions of the feeder lines which extend from the converters to closest radiating elements, bend portions which are bent in directions which the bend portions come close to each other. The partial line portions of the first and second antenna elements are disposed so as to be linearly symmetrical about a virtual line.