In riveting, it is very important to make the plate's deformation small as well as to obtain the high joint strength. Therefore, we proposed the riveting process using the washer in the same way as the bolt joint in order to accomplish both purposes. In this paper, the deformation and strength of the joints riveted using the washer were investigated. The obtained results show that the joint strength is improved while the deformation of the joint decreases. The usefulness of the proposed method was confirmed from those results.