A non-transitory computer-readable storage medium storing a program of stretching operation of an elastic membrane which can enhance elasticity of an elastic membrane in a short time without using a dummy wafer is disclosed. The non-transitory computer-readable storage medium storing a program of stretching operation of an elastic membrane in a substrate holding apparatus, the program causes a computer to perform stretching operation of supplying a pressurized fluid to a pressure chamber formed by the elastic membrane and allowing the pressure chamber to be open to the atmosphere a predetermined number of times by a pressure regulating device in a state where the substrate holding apparatus is positioned above a polishing table during standby operation of a polishing apparatus.