A method includes: vacuuming at least one area among a plurality of areas formed concentrically between a top face of the elastic film and the top ring body under a state where a bottom face of the substrate is supported by a support member and a top face of the substrate contacts a bottom face of the elastic film; measuring a flow volume of gas in an area located outside one or more areas to be vacuumed; determining whether the substrate is adsorbed to the top ring based on the flow volume of the gas; and after it is determined that the substrate is adsorbed to the top ring, separating the elastic film to which the substrate is adsorbed from the support member.