An apparatus for attaching substrates includes an upper chamber for holding an upper substrate and a lower chamber for holding a lower substrate which is to be attached to the upper substrate. The lower chamber is moved up and down so as to come together with the upper chamber to form a sealed attaching space. A substrate receiving part is fixed to a frame of the apparatus so that it does not move as the lower chamber is raised and lowered. The substrate receiving part alternatively projects from the lower chamber is the lower chamber is moved down, or is recessed into the top of the lower chamber when the lower chamber is lifted up.