Abstract: A substrate attaching device (3) includes a vacuum chamber (31), a first electrostatic chuck (32) set in the vacuum chamber, a working table (33) set below the first electrostatic chuck, a gas supply (34), a first controller (36) used to control the gas supply, and a second controller (37) used to control evacuation of the vacuum chamber. The first electrostatic chuck includes a chuck body (321) with a plurality of gas releasing holes (322). A method for attaching two substrates includes: holding a first substrate and a second substrate to the first electrostatic chuck and on the working table, respectively; moving the first electrostatic chuck and the working table closer together until they are attached together; and supplying a gas to separate the first substrate from the first electrostatic chuck, and evacuating the vacuum chamber at the same time.