An apparatus for varying the capacity in a scroll compressor, the apparatus having an orbiting scroll provided with a wrap filling portion which is stepped at a certain height, extending the entire inside of a wrap from an outer end portion of the wrap; a fixed scroll provided with a stepped wrap obtained by stepping a wrap corresponding to the wrap filling portion of the orbiting scroll and being in meshing arrangement with the orbiting scroll; a connection passage for connecting compression pockets formed by the outer wrap portion of the orbiting scroll and the inside of the wrap of the fixed scroll opposed to the outside of the outer wrap portion with the suction opening; and an opening/closing unit for opening or closing the connection passage such that the suction opening side and the compression pockets can be connected and disconnected to each other.