Anti-skid braking device with wheel speed detection means in wheel support bearing assembly

A wheel support bearing assembly for rotatably supporting a wheel 13 relative to a vehicle body structure 12 includes outer and inner members 1 and 2 with dual rows of rolling elements 3 interposed therebetween. An electric generator 4 for generating an electric power as one of the inner and outer members 1 and 2 rotates relative to the other of the inner and outer members 1 and 2 is utilized. The electric generator 4 includes a coil/magnetic element combination 17, including a ring member accommodating a coil therein, and a multi-pole magnet 18. A signal outputted from the electric generator 4 and indicative of the number of revolutions of the wheel 13 is transmitted wireless by a transmitter 5. This transmitter 5 may be an annular transmitter.