Provided is a preload inspection method for a wheel bearing device enabling more accurate checking of preload. The invention comprises: a press-fitting step S02 for press-fitting an inner ring 4 to a small-diameter stepped part 3a; a first bearing preload value calculation step S03 for calculating a first bearing preload value P1 on the basis of a first axial direction negative clearance G1; a first rotating torque measurement step S05 for measuring a first rotating torque Ta after the press-fitting step; a swaging step S06 for swaging the small-diameter stepped part to the inner ring after the first rotating torque measurement step; a second bearing preload value calculation step S07 for calculating a second bearing preload value P2 on the basis of a second axial direction negative clearance G2; a second rotating torque measurement step S08 for measuring a second rotating torque Tb after the swaging step; a third bearing preload value calculation step S09 for calculating a third bearing preload value P3 by adding, to the first bearing preload value, a preload change amount ΔP based on a differential torque ΔT between the first rotating torque and the second rotating torque; and a determination step S10 for determining the suitability of the preload from the second bearing preload value and the third bearing preload value.