Provided is an attachment for a plate denture that is less prone to malfunction even if an external force is applied thereon due to mounting or the like. The present invention is provided with: a convex element (10) that is an upper structure of a natural tooth to be maintained or an artificial root (40) and a concave element (20) that is fixed to a position of a denture base (31) corresponding to the convex element. The convex element has an engaging portion (11), and a connecting portion (12) for connecting the engaging portion to the natural tooth or the artificial root, with the connecting portion having a section narrower than the engaging portion. The concave element is provided with: a main body (21) having the shape of a bottomed cylinder, with the main body (21) having a bottom (21a) on one end thereof, an opening (21b) on the other end thereof, and a hollow portion (21c) for inserting the engaging portion a ring-shaped groove (21e) formed in an inner circumferential surface of the main body along the circumferential direction thereof an O-ring (22) having an outer circumferential portion that fits within the groove, with the inner diameter of the O-ring (22) being smaller than the engaging portion and a drainage channel (21f) communicating between the hollow portion and the outside of the main body through the groove.La présente invention concerne une fixation pour une prothèse dentaire en plaque qui est très peu susceptible de mauvais fonctionnement même si une force externe est appliquée sur celle-ci en raison du montage ou équivalent. La présente invention comprend : un élément convexe (10) qui est une structure supérieure dune dent naturelle à conserver ou une racine artificielle (40) et un élément concave (20) fixé à une position dune base de prothèse dentaire (31) correspondant à lélément convexe. Lélément convexe a une partie de mise en prise (11) et une partie de raccordement (12) pour raccorder la partie de mise en prise à la dent naturelle ou à l
