A roller bearing apparatus provided with a roller bearing having an outer ring with a cylindrical opening that opens at one end and a cover fitted in the opening against the inner periphery thereof to close it. The cover is provided with an inscribing surface that inscribes the. inner periphery of the opening and a stepped surface that protrudes radially outward from the inscribing surface to abut the axial end face of the opening. The axial end face of the opening is provided with a beveled part on the inner rim. An annular space formed by the beveled part, inscribing surface, and stepped surface is filled with sealant.