A substrate conveying system includes a substrate supply unit including a movable rack and an up-down unit which moves the movable rack down, a lift unit which has one or more ejection holes which eject a gas upward and is configured to lift-up the substrate supported on the movable rack by the pressure of the gas ejected through ejection holes when the up-down unit moves the movable rack down, and a conveying unit which includes a conveyor, and hook elements extending upward from the conveyor, and is configured to push in a conveying direction the substrate W being lifted-up by the pressure of the gas ejected through the ejection holes.