A keeper tray corresponding to a removable keeper is used for casting a root cap for a dental magnetic attachment having a space S, in which the keeper is inserted and adherently fixed, by a lost wax method. The keeper tray corresponding to the removable keeper is made of a synthetic resin or a metal and has the formed space S thereon. The keeper tray corresponding to the removable keeper has a shape in which an opening 2 is formed on the bottom surface 1 by cutting out from an outer peripheral portion 1 a of the bottom surface 1 to a center portion, and opens to a space S.
