An organic layer deposition apparatus including an electrostatic chuck combined with a substrate so as to fixedly support the substrate. The organic layer deposition apparatus including a receiving surface that has a set curvature for receiving the substrate; a deposition source for discharging a deposition material toward the substrate; a deposition source nozzle unit disposed at a side of the deposition source and including a plurality of deposition source nozzles arranged in a first direction; and a patterning slit sheet disposed to face the deposition source nozzle unit, and having a plurality of patterning slits arranged in a second direction perpendicular to the first direction, wherein a cross section of the patterning slit sheet on a plane formed by lines extending in the second direction and a third direction is bent by a set degree, wherein the third direction is perpendicular to the first and second directions.