To support a load moment applied to the direct acting bearing of a direct acting shaft of a robot by a simple constitution.

The structure of a direct acting shaft is formed on the base plate 2 fixed on the base 1 of a robot. The coil part 31 and magnet part 32 of a linear motor for driving the direct acting shaft are laid facingly at some intervals on the lower surface of arm supporter 10 and the base plate 2, respectively. Main and sub direct acting bearing parts MB, SB arranged by sandwitching the magnet part 32 are constituted by the rollers 41, 42 and the guide surfaces 241-244 with a simple structure respectively. On the arm 20 combined with one end of the arm supporter 10, a direct acting shaft 21 for driving a writs part 22 is installed as the shaft of the direct acting shaft rear step and an end effector 23 of a hand is installed on a wrist part 22. The attraction force generated between the coil part 31 and magnet part 32 is utilized as a balance force for acting to a direction for reducing a load moment acting around the direct acting shaft for the main direct acting MB. It is not mind saving the sub direct acting bearing by adding a gutter shape guide to the main direct acting bearing.