PURPOSE: To provide the desired dynamic pressure groove depth by reciprocating a taper member in the axial direction and increasing or decreasing the outer peripheral enveloping surface diameter of multiple steel balls.

CONSTITUTION: When a taper member 5 is screwed in, a shaft 1 is acted to be expanded by the taper member 5 coupled with a tapered hole 4. The shaft 1 is applied with the acting force in the outer peripheral direction, it is easily deformed by the existence of slits 3, 3, and it is gradually expanded in diameter. When the shaft 1 is expanded in diameter, the diameter size D of steel balls 2, 2 fixed to the outer periphery section 8 of the shaft 1 is increased, and the groove depth of the dynamic pressure generating groove formed on the inner periphery of a sleeve bearing is increased. When sleeve bearings required for various groove depths are machined, only the screwing in or out of a taper member 5 or a screw member is required, and the labor for removing and replacing various corresponding manufacturing devices can be omitted.