An underground radar device and a method thereof are provided that do not require replacement of antennas for transceiving in conformity with the width of a road, and can achieve exploration of a buried object with a single scan. An underground radar device includes a transmission array antenna and a reception array antenna, and further includes a position variable mechanism capable of changing intervals between antenna elements of the transmission array antenna and the reception array antenna while keeping all the intervals equal. The position variable mechanism includes a drive unit, a plurality of crossbars constituting an expandable link, and a plurality of link sections for coupling so as to change inclination angles of a V-shape and an inverted V-shape of the expandable link.
展开▼
