A target device, which allows a sufficient amount of reflected light to be obtained from an end portion, is provided and includes a measurement section. In the target device, a retroreflective layer in which a plurality of retroreflective elements are arranged on the entire circumference in a circumferential direction about an axis is formed on at least part of the outer peripheral surface of the measurement section. The retroreflective layer is formed into an uneven shape in which a distance from the axis changes along the entire circumference in the circumferential direction.