Each of the plurality of transmission antenna groups includes a plurality of transmission antennas that are disposed at second intervals in a first direction, and are disposed at fourth intervals each of which is an interval of an integral multiple of a third interval in a second direction. Each of the plurality of reception antenna groups includes a plurality of reception antennas that are disposed at fifth intervals in the first direction, and are disposed at sixth intervals each of which is an interval of an integral multiple of the third interval in the second direction. The difference between the second interval and the fifth interval is the first interval, and the difference between the fourth interval and the sixth interval is the third interval.