Abstract: Provided is a three-dimensional measurement device applicable to a machining machine. A sensor head contains a body and a collet chuck. A light emitting window and a light receiving window are provided on the front end of the body. A non-contact sensor is incorporated in the body. Laser light emitted by the non-contact sensor is radiated onto a workpiece through the light emitting window. Laser light reflected from the surface of the workpiece is received by the light receiving window. A collet chuck is attached to the rear end of the body. The collet chuck has the same shape as a collet chuck provided by each tool housed in a tool magazine of a machining center.