A method of producing a bonded wafer, comprising: implanting hydrogen ions, rare gas ions, or mixed gas ions thereof into a bond wafer from a surface of the bond wafer to form a layer of the implanted ions in an interior of the bond wafer; bonding the surface from which the ions are implanted into the bond wafer and a surface of a base wafer; and then separating the bond wafer along the layer of the implanted ions by performing a separation heat treatment on the wafers after the bonding step by using a heat treatment furnace such that the bonded wafer is formed, wherein wafers each having a cutout portion which is a notch are used as the bond wafer and the base wafer, and characterized in that either or both of settings of an ion implanter with which the ions are implanted and conditions of the ion implantation are adjusted in the step of implanting the ions such that the cutout portion of either or both of the bond wafer and the base wafer after the bonding step is located at within a range of 0±30° or 180±30° from a position at which the separation of the bond wafer begins in the step of separating the bond wafer, and one or more of the following to is performed for adjusting either or both of the settings of the ion implanter and the conditions of the ion implantation; the step of implanting the ions includes arranging the bond wafer in the ion implanter such that a position of the cutout portion of the bond wafer or a position of 180° away from the cutout portion of the bond wafer matches a position at which damage due to the ion implantation is comparatively large in a plane of the bond wafer, the damage being determined by the ion implanter and the conditions of the ion implantation, in the step of implanting the ions, an amount of the implanted ions at the position of the cutout portion of the bond wafer or the position of 180° away from the cutout portion of the bond wafer is larger than at other positions, the step of implanting the ions includes arranging the bond wafer on a heat sink such that the position of the cutout portion of the bond wafer or the position of 180° away from the cutout portion of the bond wafer matches a position at which thermal conduction of the heat sink when the ions are implanted is comparatively poor in a plane of the bond wafer. implanting hydrogen ions, rare gas ions, or mixed gas ions thereof into a bond wafer from a surface of the bond wafer to form a layer of the implanted ions in an interior of the bond wafer; bonding the surface from which the ions are implanted into the bond wafer and a surface of a base wafer; and then separating the bond wafer along the layer of the implanted ions by performing a separation heat treatment on the wafers after the bonding step by using a heat treatment furnace such that the bonded wafer is formed, wherein wafers each having a cutout portion which is a notch are used as the bond wafer and the base wafer, and characterized in that either or both of settings of an ion implanter with which the ions are implanted and conditions of the ion implantation are adjusted in the step of implanting the ions such that the cutout portion of either or both of the bond wafer and the base wafer after the bonding step is located at within a range of 0±30° or 180±30° from a position at which the separation of the bond wafer begins in the step of separating the bond wafer, and one or more of the following to is performed for adjusting either or both of the settings of the ion implanter and the conditions of the ion implantation; the step of implanting the ions includes arranging the bond wafer in the ion implanter such that a position of the cutout portion of the bond wafer or a position of 180° away from the cutout portion of the bond wafer matches a position at which damage due to the ion implantation is comparatively large in a plane of the bond wafer, the damage being determined by the ion implanter and the conditions of the ion implantation, in the step of implanting the ions, an amount of the implanted ions at the position of the cutout portion of the bond wafer or the position of 180° away from the cutout portion of the bond wafer is larger than at other positions, the step of implanting the ions includes arranging the bond wafer on a heat sink such that the position of the cutout portion of the bond wafer or the position of 180° away from the cutout portion of the bond wafer matches a position at which thermal conduction of the heat sink when the ions are implanted is comparatively poor in a plane of the bond wafer. the step of implanting the ions includes arranging the bond wafer in the ion implanter such that a position of the cutout portion of the bond wafer or a position of 180° away from the cutout portion of the bond wafer matches a position at which damage due to the ion implantation is comparatively large in a plane of the bond wafer, the damage being determined by the ion implanter and the conditions of the ion implantation, in the step of implanting the ions, an amount of the implanted ions at the position of the cutout portion of the bond wafer or the position of 180° away from the cutout portion of the bond wafer is larger than at other positions, the step of implanting the ions includes arranging the bond wafer on a heat sink such that the position of the cutout portion of the bond wafer or the position of 180° away from the cutout portion of the bond wafer matches a position at which thermal conduction of the heat sink when the ions are implanted is comparatively poor in a plane of the bond wafer.