A bonded wafer is produced by comprising a step of implanting oxygen ions from a surface of a wafer for active layer to form an oxygen ion implanted layer at a given position inside the wafer for active layer; a step of bonding the wafer of active layer to a wafer for support substrate directly or through an insulating film; a step of subjecting the resulting bonded wafer to a heat treatment for increasing a bonding strength; a step of removing a portion of the wafer for active layer in the bonded wafer to a given position not exposing the oxygen ion implanted layer by a given method; a step of exposing the entire surface of the oxygen ion implanted layer; and a step of removing the exposed oxygen ion implanted layer to obtain an active layer of a given thickness, wherein the step of exposing the entire surface of the oxygen ion implanted layer is carried out by a dry etching under given conditions.