A wheel bearing apparatus has an outer member with a body mounting flange and double row outer raceway surfaces, an inner member with double row inner raceway surfaces opposing the double row outer raceway surfaces, and double row rolling elements contained between the inner raceway surfaces and the outer raceway surfaces, respectively, of the inner member and the outer member. A plurality of bolt insertion holes formed in the outer member body mounting flange. An abutment surface, to abut against the body-side member, is formed around each bolt insertion hole as a surface projecting from the inner-side surface of the body mounting flange with a step height. A relative difference between the step heights of the abutment surfaces is limited to a minimum.