PURPOSE: To apply load substantially equally to the respective balls by aligning the centers of virtual circles of a load ball groove and a ball rolling groove with the center of a circle of a raceway rail and to improve sliding accuracy and rigidity by applying pre-load.

CONSTITUTION: A curve sliding bearing comprises a sliding table 1 which is provided with a cover 2 and includes four ball endless raceways comprising a load ball groove 8 and a no-load ball passage 9, a raceway rail 3 including a ball rolling groove 11 confronting with the load ball groove 8 of the ball endless raceway, and many balls 4 adapred to roll while loading in four directions between the load ball groove 8 and the ball rolling groove 11. The raceway rail 3 is formed like a circular-arc and the centers of virtual circles of each load ball groove 8 on the sliding table 1 side and each ball rolling groove 11 on the raceway rail 3 side are aligned with the center of a virtual circle of the raceway rail 3. Accordingly, curve sliding guide can be performed while putting load in four directions through the balls 4 between the sliding table 1 and the raceway rail 3, and pre-load can be applied.