To provide a dustproof cover device for machine tool which is installed in compact form within the moving range of a moving body and which prevents biting-in of the chip to ensure a stable operation for a long period of time.

The tool rest of a lathe is equipped with a dustproof cover device 11 at a vertical open face 4a of a machine frame 4 on which a turret 5 travels. The cover device 11 is composed of a base cover 12 secured to the turret 5, an end cover 13 farthest from the turret 5 and five intermediate covers 14 positioned between them, and seven pieces of covers 12-14 are overlapped one over another in such a way as slidably with one another. The end cover 13 and intermediate cover 14 are formed in L-shape from guides 13a and 14a extending in the moving direction over the turret 5 and enclosures 13b and 14b spreading in the vertical open face 4a. The end cover 13 is energized by a spring 16 toward the turret 5, and its enclosure 13b is arranged as capable of moving to inside and outside of the machine frame 4.