It is intended to prevent a pelvic organ from slipping out of the body by pushing up the organ having slipped out or just before slipping out. A device for preventing and treating pelvic organ prolapse characterized by comprising a convex push-up member which is made of a flexible material showing a pressing force toward a pelvic organ prolapse site of a wearer and in which the surface to be in contact with the pelvic organ is coated with a coating sheet, or a concave member which is made of a flexible material receiving the pelvic organ prolapse site and in which the surface to be in contact with the pelvic organ is coated with a coating sheet, and a means of holding the convex push-up member or the concave member for tightly pressing the convex push-up member or the concave member to the pelvic organ prolapse site of the wearer as described above.