To provide an assembly method for a roller bearing capable of securing the integration of cage segments, rollers and an inner ring to allow easy assembly.

The assembly method for a tapered roller bearing includes a step of temporarily fixing a body part 11a of a temporary fixture 11 to an end face 3d of an inner ring 3 in the state of protruding an inclined part 11b of the temporary fixture 11 radially outward of the inner ring 3, a step of annularly arranging cage segments 6 on the outer periphery of the inner ring 3, a step of inserting tapered rollers 4 into pockets of the cage segments 6, a step of inserting temporarily fixing pins 12 into first and second hole portions 21a, 22a formed in first and second rim parts 21, 22, respectively, and through-holes 4a passing through the tapered rollers 4 in the axial direction to fix the temporarily fixing pins 12 to the temporary fixture 11, and a step of fitting the inner ring 3 into an outer ring so that the outer raceway surface of the outer ring has external contact with the tapered rollers.