A roller bearing assembly apparatus comprising: an insertion jig for assembling a roller group of plural rollers that are aligned in parallel to each other in an annular shaped alignment space on an inside of a race member having a race surface formed around an inner-circumferential surface thereof, the insertion jig comprising: a guide member having a guide hole though which the roller group that is pushed out in an axial direction from the alignment space can be inserted, the roller bearing assembly apparatus being characterized in that it further comprises: a retaining member made of an elastic material, the retaining member located inside the guide hole, and the retaining member capable of being inserted, in a state in which a diameter thereof is elastically reduced, inside the roller group that is inserted inside the guide hole; a guide rod located inside the guide hole in series with the retaining member in the axial direction; and a push-out cylinder inserted into the guide hole and provided around the retaining member and the guide rod; and by causing the push-out cylinder to displace in the axial direction relative to the guide member, the roller group and the retaining member that is inserted inside the roller group can be simultaneously pushed out in the axial direction from the guide hole, and then can be simultaneously assembled inside the race member. an insertion jig for assembling a roller group of plural rollers that are aligned in parallel to each other in an annular shaped alignment space on an inside of a race member having a race surface formed around an inner-circumferential surface thereof, the insertion jig comprising: a guide member having a guide hole though which the roller group that is pushed out in an axial direction from the alignment space can be inserted, the roller bearing assembly apparatus being characterized in that it further comprises: a retaining member made of an elastic material, the retaining member located inside the guide hole, and the retaining member capable of being inserted, in a state in which a diameter thereof is elastically reduced, inside the roller group that is inserted inside the guide hole; a guide rod located inside the guide hole in series with the retaining member in the axial direction; and a push-out cylinder inserted into the guide hole and provided around the retaining member and the guide rod; and a guide member having a guide hole though which the roller group that is pushed out in an axial direction from the alignment space can be inserted, the roller bearing assembly apparatus being characterized in that it further comprises: a retaining member made of an elastic material, the retaining member located inside the guide hole, and the retaining member capable of being inserted, in a state in which a diameter thereof is elastically reduced, inside the roller group that is inserted inside the guide hole; a guide rod located inside the guide hole in series with the retaining member in the axial direction; and a push-out cylinder inserted into the guide hole and provided around the retaining member and the guide rod; and by causing the push-out cylinder to displace in the axial direction relative to the guide member, the roller group and the retaining member that is inserted inside the roller group can be simultaneously pushed out in the axial direction from the guide hole, and then can be simultaneously assembled inside the race member.