A ball screw mechanism includes a ball nut member that threadedly engages with a rack shaft via a plurality of balls, and a rolling bearing including an outer ring retained by a housing, an inner ring retained by the ball nut member, and a plurality of rolling elements. The ball screw mechanism moves the rack shaft in an axial direction relative to the housing through rotation of the ball nut member. A method for inspecting the ball screw mechanism includes fixing the outer ring to a fixing jig, pressing the rack shaft in the axial direction while restricting its rotation to rotate the ball nut member together with the inner ring relative to the outer ring, measuring an amount of a run-out of the rack shaft along with the rotation of the ball nut member, and determining whether the amount of the run-out satisfies a predetermined condition.