SURVEYING INSTRUMENT

In a surveying instrument including an instrument height measuring unit configured to make a distance measurement by emitting distance-measuring light to a distance-measuring object below a vertical axis of a surveying instrument main body, and an arithmetic unit configured to calculate a distance to the distance-measuring object by analyzing light being the distance-measuring light that has returned by being reflected by the distance-measuring object, and calculate an instrument height, the instrument height measuring unit is configured to make a distance measurement by irradiating the distance-measuring light toward a predetermined region of the distance-measuring object centered on a point below the vertical axis of the surveying instrument main body, and the arithmetic unit is configured to calculate the instrument height by operating an average value of distance-measurement values in the region. By calculating an average value of results of distance measurements of a predetermined region, the measurement accuracy can be improved.