To provide a bearing device to be incorporated at a high precision position and not to require large force for incorporating and removing it and its incorporating and removal method.

A means to push in an inner ring is constituted of a flange member 9 arranged in a groove 10 of a sleeve adjacent to one side surface of the inner ring and positional movement of which is regulated to the axial position. The flange member 9 has at least two through holes arranged at equal positions in the peripheral direction to receive a pressure member 11 and extending in the axial direction, it is made possible to push up an inner ring 6 on a peripheral surface of the sleeve 7 by moving the pressure member 11 against the inner ring, the through holes formed on the flange member 9 are screw holes, the pressure member 11 to pressurize the inner ring 6 are a plural number of set screws 11, and each of the set screws 11 is respectively arranged on each of the screw holes.