A surveying instrument comprises a rotation unit (7) adapted to direct a distance measuring optical axis to an object to be measured. A rotary drive unit (5) rotates the rotation unit (7) . A rotary drive unit (5) comprises a rotary motor (14, 16) for rotating an output shaft (6) and a clutch unit (15, 17) for connecting and disconnecting the rotary motor and the output shaft. The rotary motor (14, 16) and the clutch unit (15, 17) are arranged in series along the output shaft (6) and the output shaft (6) is fixed to the rotation unit (7).
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