A tapered roller bearing apparatus includes: an outer ring that includes an outer-ring raceway formed in an inner circumferential surface thereof; an inner ring which includes a large-diameter portion having a cylindrical portion with a substantially uniform outer diameter, a large rib portion having an outer circumferential surface and a guide surface continued to the outer circumferential surface, an inner-ring raceway, and a small-diameter cylindrical portion which are sequentially formed from one end to the other end, and are subjected to a heat treatment to have a surface-hardened layer; and a plurality of tapered rollers which are rollably disposed between the inner-ring raceway and the outer-ring raceway, a large-diameter end surface of the tapered roller being guided by the guide surface. An angle formed between the guide surface and the outer circumferential surface is obtuse.