Bearing device for wheel

A hub wheel and an outer joint member are coupled to each other through intermediation of a recess-projection fitting structure. The recess-projection fitting structure can be separated by being applied with a pulling-out force in an axial direction under a state in which a bolt member is removed, and can be re-formed by re-screwing the bolt member into a bolt hole. The hub wheel comprises a receiving portion for receiving the bolt member. A guide portion for guiding the press-fitting of the projection portion is provided at an end portion on a press-fitting start side of the shaft portion of the outer joint member or the hole portion of the hub wheel. A length of the bolt member is set so that at re-assembly of the recess-projection fitting structure after separation of the recess-projection fitting structure, a male threaded portion of the bolt member having a seat surface held in abutment against the receiving surface is free from being engaged with a female threaded portion of the bolt hole until an end portion on the press-fitting start side of the projection portion is fitted to the guide portion. This structure makes it possible that the hub wheel and the outer joint member are coupled and re-coupled to each other with high accuracy even after being separated from each other.