To provide a wheel bearing device capable of preventing occurrence of such a situation that a drive shaft can not be spline-fitted to an inner periphery of an inner shaft.

A wheel bearing device 1 includes an inner shaft 2 and an inner ring member 9 externally fitted onto an outer circumference of an axially-inner end portion of the inner shaft 2. A shaft portion 31 coupled to the inner shaft 2 so as to be integrally rotatable with the inner shaft is inserted in a center hole 12 of the inner shaft 2. Spline grooves 13 to be spline-fitted to a large number of spline teeth 32 formed on an outer circumference of the shaft portion 31 are formed in an inner periphery 12a of the center hole. An annular clearance S that suppresses reduction in a diameter of the inner shaft 2 by externally fitting the inner ring member 9 onto the inner shaft 2 is formed between the inner ring member 9 and the axially-inner end portion of the inner shaft 2, within a range where an axial range in which the spline teeth 32 are formed overlaps with an axial range of the inner ring member 9.