There is disclosed a pessary 10 for treating the prolapse of uterus, characterized by comprising a cylindrical sheet-like member 11, which is un-deformable in the axial direction but deformable in the radial direction. The sheet-like member 11 comprises a plurality of metal pieces 13 discontinuously provided in the circumferential direction at intervals of a gap 12 having a predetermined length, and silicon portions 14 continuously provided in the circumferential direction to coat each metal piece 13. Silicon portions 14a provided in the gap 12 are deformable in the radial direction.