The surveying device main unit includes: a distance-measuring light-emitting unit; a light-receiving unit; a distance-measuring unit; an optical axis-deflecting unit; an emitting direction-detecting unit; and an arithmetic control unit. The arithmetic control unit controls two-dimensional scanning with a scanning pattern having an intersection at which an outward passage and a return passage of the two-dimensional scanning intersect, updates three-dimensional data of the measurement target each time a light-receiving signal is detected during the two-dimensional scanning, generates weights for detecting a reference point of the measurement target and for detecting a rotation angle of the measurement target in accordance with the distance from the intersection, each time the three-dimensional data is updated, and tracks the measurement target based on the reference point position and the rotation angle of the measurement target calculated using the weights.