PURPOSE: To prevent the lateral force perpendicular to the guide direction from acting on a machine part by forming at least two slits axially separated one another on a pipe as a connecting member which transmits the feeding motion of a spindle transmitting device.

CONSTITUTION: A spindle nut 10 is rotated through a belt transmitting device 8 by the driving of an electric motor 6, and slided along a smooth spindle 7 for linearly guiding a machine part 3 along a guide rod 2 on a measurement table 1 through a pipe 17 surrounding the spindle 7. the pipe 17 as a connecting member comprises two pairs of radial slits 18a-18d separated from one another near both ends thereof in such manner that the webs 19a-19d, 21a-21d are remained, whereby the pipe becomes elastically flexible, and can be prevented from adding undesired lateral force to the machine part 3. The accuracy of the machine part, that is, a coordinate measuring device can be improved, and the generation of the vibration can be inhibited.