Abstract: In a method for producing a bonded wafer comprising an ion implantation step where at least either hydrogen ions or rare gas ions are implanted into a first wafer from its surface to form a micro bubble layer (implanted layer) in the first wafer, a bonding step wherein the surface subjected to the ion implantation of the first wafer is bonded to a surface of a second wafer, and a delamination step where the bonded first wafer and second wafer are subjected to a heat treatment to delaminate the first wafer at the micro bubble layer, wherein the ion implantation is performed while temperature of the first wafer is maintained at a temperature lower than 20° C. in the ion implantation step.