A method for manufacturing an SOI wafer by bonding a single crystal silicon wafer to a transparent insulation substrate being a synthetic silica substrate, and thereafter making the single crystal silicon wafer to be thinned to form an SOI layer on the transparent insulation substrate, the manufacturing method performing at least: a step of forming an ion injection layer within the single crystal silicon wafer, by injecting at least one of a hydrogen ion and a rare gas ion from a surface of the single crystal silicon wafer with an ion injecting dose equal to or greater than 8x10 16 /cm 2; a step of placing the single crystal silicon wafer in a vacuum chamber; a step of introducing a hydrogen gas, an argon gas, a mixture gas thereof, or a mixture gas of a hydrogen gas and a helium gas as a plasma gas into the vacuum chamber; a step of performing plasma processing on the ion injection surface of the single crystal silicon wafer by subjecting the ion injection surface of the single crystal silicon wafer to high frequency plasma; a step of placing the transparent insulation substrate in a chamber into which atmospheric air is introduced; a step of introducing a nitrogen gas or an argon gas as a plasma gas into the chamber; a step of performing ozone processing on a surface of the transparent insulation substrate by generating high frequency plasma to convert oxygen in the atmospheric air into ozone; a step of bonding the ion injection surface of the single crystal silicon wafer to a surface of the transparent insulation substrate, by bringing them into contact with each other at room temperature, with the processed surfaces as bonding surfaces; a step of raising a bonding strength by performing thermal processing to the bonded wafer under a temperature of 100-300 degrees centigrade; and a step of forming an SOI layer on the transparent insulation substrate, by mechanically peeling the single crystal silicon wafer by giving an impact to the ion injection layer; wherein the step of raising the bonding strength is performed after the step of bonding and before the step of forming an SOI layer. a step of forming an ion injection layer within the single crystal silicon wafer, by injecting at least one of a hydrogen ion and a rare gas ion from a surface of the single crystal silicon wafer with an ion injecting dose equal to or greater than 8x10 16 /cm 2; a step of placing the single crystal silicon wafer in a vacuum chamber; a step of introducing a hydrogen gas, an argon gas, a mixture gas thereof, or a mixture gas of a hydrogen gas and a helium gas as a plasma gas into the vacuum chamber; a step of performing plasma processing on the ion injection surface of the single crystal silicon wafer by subjecting the ion injection surface of the single crystal silicon wafer to high frequency plasma; a step of placing the transparent insulation substrate in a chamber into which atmospheric air is introduced; a step of introducing a nitrogen gas or an argon gas as a plasma gas into the chamber; a step of performing ozone processing on a surface of the transparent insulation substrate by generating high frequency plasma to convert oxygen in the atmospheric air into ozone; a step of bonding the ion injection surface of the single crystal silicon wafer to a surface of the transparent insulation substrate, by bringing them into contact with each other at room temperature, with the processed surfaces as bonding surfaces; a step of raising a bonding strength by performing thermal processing to the bonded wafer under a temperature of 100-300 degrees centigrade; and a step of forming an SOI layer on the transparent insulation substrate, by mechanically peeling the single crystal silicon wafer by giving an impact to the ion injection layer; wherein the step of raising the bonding strength is performed after the step of bonding and before the step of forming an SOI layer.