To sufficiently show the rod protecting function of a hydraulic cylinder with a cover member, to reduce the generation of noise, and to improve the connecting strength.

In order to protect the rod of the hydraulic cylinder, this cylinder cover device is formed of a guide member 21 fixed to a cylinder tube 11 and a cover member 22 fixed to an end of the rod by screws at one end thereof and to be guided by the guide member 21. The cover member 22 covers the rod when it is extended at the maximum, and a plate spring 24 works between the guide member 21 and a cover main body part 22a of the cover member 22, and a plate spring 25 works between the guide member 21 and a side part 22b of the cover member 22. Furthermore, lubricating members 26-28 made of a synthetic resin having excellent sliding property are installed in slide- contact parts of both the plate spring 24, 25 between the guide member 21 and the engagement part 22c of the cover member 22.