A sheet-affixing device for affixing a pressure sensitive adhesive-sheet onto a wheel is provided. The sheet-affixing device comprises an absorption plate member, an alignment shaft member, and a pressing member. The absorption plate member is formed in a ring-shape. The exterior diameter of the absorption plate member is smaller than the diameter of a rim. On the bottom surface of the absorption plate member there are provided a plurality of suction perforations. The alignment shaft member is fitted into the hub so that the center of the absorption plate member and the center of the wheel are aligned. The pressing member is used for pressing a peripheral part of the pressure sensitive adhesive-sheet against the rim so that the peripheral part is affixed to the rim. Further, the pressing member is movable relative to the absorption plate member along the axial direction of the ring-shaped absorption plate member.