To provide a protection device for a wire saw apparatus which can easily be post-attached to a saw wire and makes the orientation of adjacent pulleys freely selectable.

The protection device for the wire saw apparatus 5 has at least two cover elements 12 and 13 which are extractable, insertable and slidable from and with each other. In the cover elements 12 and 13, in the protection device having an accommodating space 14 for a saw wire 8 extending in the longitudinal direction and voids 15 and 16 extending in the longitudinal direction, the cover elements 12 and 13 are tube elements, and at least one, preferably, all the tube elements have circular cross sections. Each of fixing devices 18 and 20 is installed at one end 17 or 19 of each cover element 12 or 13, and the cover elements 12 and 13 are made possible to be fixed to the pulleys 6 and 7 of the wire saw apparatus 5.