PURPOSE: To prevent the abrasion and seizure of a sliding face and obtain low friction by pivotally rotatably providing a roller on a fixed shaft which is fixed to a supporting member and forming dynamic pressure grooves on the contact face between the fixed shaft and the roller.

CONSTITUTION: Both ends of a fixed shaft 11 is fixed to the end portion of a supporting member 10 consisting of a pair of parallel arms at a certain interval, and a roller 12 is rotatably installed on the fixed arm 11. A plurality of angle-shaped dynamic pressure grooves 13 are continuously formed in the circumferential direction on the contact face portion between the outer peripheral face of the fixed shaft 11 and the inner peripheral face of the roller 12. A fluid cushion generated by a dynamic pressure is formed on the sliding face between the fixed shaft 11 and the roller 12, which is borne by means of this fluid cushion. Thereby, the abrasion and seizure of the sliding face can be prevented while obtaining low friction.