Abstract: A focusing apparatus for a surveying instrument including an objective lens, a focusing lens and a reticle. The focusing lens is movable in an optical axis direction, by a rotating shaft member which is rotated by a motor, to form an image, of an object to be surveyed, on the reticle. Means for detecting a focus state of the object image and for controlling the motor in accordance with the detected focus state are provided. A focusing knob, coaxial with the rotating shaft member, and movable in an axial direction thereof is also provided. A plurality of clutches disengageably engages the focusing knob or the motor with the rotating shaft member, according to an axial movement of the focusing knob.