COORDINATE MEASURING INSTRUMENT

The present invention provides a coordinate measuring instrument which measures an auxiliary measuring device by tracking the auxiliary measuring device. The coordinate measuring instrument includes: a base and an optical mechanism disposed on the base; the optical mechanism includes a first rotating device mounted on the base, a second rotating device disposed on the first rotating device, and an optical body mounted on the second rotating device, and a first axis is orthogonal to a second axis; the optical body has a housing, a laser source disposed in the housing and emitting laser beams, a beam tracker for capturing the laser beams reflected by the auxiliary measuring device to track the laser beams, and an optical distance meter for measuring a distance from the auxiliary measuring device; the housing includes a first housing, a second housing, and a functional housing disposed between the first housing and the second housing; and the optical distance meter includes an interferometric distance measuring unit and an absolute distance measuring unit which are disposed inside the optical body.