To improve straight performance of a telescopic cover by forming the telescopic cover by telescopically connecting plural movable plates, installing sliders on the respective movable plates, fixing rails for sliding the sliders to a machine body, and forming a direct acting guide of the telescopic cover out of the rails and the sliders.

A telescopic cover 1 is formed by telescopically connecting plural movable plates 3. A direct acting guide 2 is composed of sliders 6 installed on the respective movable plates 3, rails 7 for sliding the sliders 6 and fixing plates 9 for fixing the rails 7 to a machine body 8 of a machine tool. Since the direct acting guide 2 guides the telescopic cover 1 in a sliding guide system, the sliders 6 and the rails 7 can be closely easily installed to improve straight performance of the telescopic cover 1, so that the telescopic cover 1 can be telescoped at a high speed, durability can be enhanced, and vibration and noise at starting stopping time can be restrained.