A substrate cleaning apparatus cleans a surface of a substrate such as a semiconductor wafer and dries the substrate. The substrate cleaning apparatus includes a process chamber having a substrate conveying unit configured to hold a substrate horizontally with its upper surface facing upwardly and to convey the substrate in one direction, and a cleaning unit configured to clean the surface of the substrate in non-contact state by supplying a cleaning liquid to the surface of the substrate which is moving in the process chamber. The substrate apparatus has an inert gas blowing unit configured to blow an inert gas toward the front and reverse surfaces of the substrate which has been cleaned in the cleaning unit to produce an inert gas atmosphere in the process chamber while drying the substrate with the inert gas.