There are provided a horizontal angle detector for detecting a horizontal angle, an elevation angle detector for detecting an elevation angle, a dynamic displacement detector for detecting posture displacement of a surveying instrument main unit in two horizontal directions, and a calculating unit, wherein the dynamic displacement detector detects displacement with respect to standard posture of the surveying instrument main unit 1, the calculating unit calculates the horizontal angle and the elevation angle corresponding to dynamic displacement detected by the dynamic displacement detector, and compensates the horizontal angle and the elevation angle obtained by the horizontal angle detector and the elevation angle detector respectively are compensated based on the calculated horizontal angle and the calculated elevation angle.