To eliminate the occurrence of buckling at a needle roller when the roller is axially compressed so that an oblique surface is formed on its end.

The apparatus for compressing the needle rollers forms the oblique surface on the outer peripheral part of the boundary between the end 40 and the side face 42 of the rollers 4 by axially compressing the rollers 4. The apparatus comprises tapered surfaces 26, 36 of a range not exceeding 45° with respect to the axial direction of the rollers 4 engaged with recesses 25, 35 for engaging and compressing the rollers 4 at the boundaries between the bottoms 21, 31 of the recesses 25, 35 and the side faces 22, 32. Thus, the rollers 4 engaged with the recesses 25, 35 in the range of the tapered surfaces 26, 36 are axially compressed.