To enable accurate positioning by a simple operation without preparing a special component.

This centering and positioning device 10 positioning and fixing a second member 3 to a first member 1 comprises a positioning body 11 capable of penetrating holes respectively provided on the first member 1 and a second member 3, a plurality of expansion pieces 18 radially disposed in relation to the positioning holes, 2, 4 inner surfaces of the first and second members 1, 3 radially expandable and contactable and a pair of two operating shafts 20, 30 applying thrust to press tapered surfaces 21, 31 on the expansion pieces 18 to be pushed out of the outer periphery to abut on and to be held by the members 1, 3, and centering them. When the operating shafts 20, 30 are advanced in the axial direction, the expansion pieces 18 are pushed out, and when the operating shafts 20, 30 are retreated, the expansion pieces 18 are stored in the positioning body 11.