The present invention provides a method for manufacturing an SOI wafer including a step of forming an insulator film on an entire surface of a bond wafer before bonding, bringing a bonded wafer before delaminating the bond wafer at an ion implanted layer into contact with a liquid that enables dissolving the insulator film while protecting the insulator film on a back surface on the opposite side of a bonding surface of the bond wafer, or exposing the bonded wafer to a gas that enables dissolving the insulator film, and thus etching the insulator film placed between the bond wafer and a base wafer from an outer peripheral end of the bonded wafer toward a center of the bonded wafer.