A wheel bearing apparatus with an incorporated wheel speed detecting apparatus has an outer member with double row outer raceway surfaces formed on its inner circumferential surface. An inner member includes a wheel hub with an integrally formed wheel mounting flange at one end. A cylindrical portion axially extends from the wheel mounting flange. An inner ring is fit onto the cylindrical portion of the wheel hub. Double row inner raceway surfaces, opposite to the double row outer raceway surfaces, are formed on the outer circumferential surfaces of the wheel hub and inner ring, respectively. Double row rolling elements are arranged between the outer and inner raceway surfaces. An encoder is mounted on the outer circumferential surface of the inner ring. An annular sensor holder is arranged on the end of the outer member opposite to the encoder. A wheel rotation speed detecting sensor is integrally molded with the sensor holder and arranged opposite to the encoder, via a predetermined radial gap. The encoder has an annular ring configuration with its characteristics alternately and equidistantly varying along its circumferential direction. A seal is arranged at the inboard side of the encoder via the sensor holder. The seal includes a first annular sealing plate and a second annular sealing plate. The first and second annular plates are mounted on the sensor holder and the inner ring, respectively, and opposite toward each other.