A substrate is moved in a linear direction simultaneously between a processing face of an upper proximity head and a processing face of a lower proximity head. As the substrate is moved, a first meniscus of processing liquid is generated between the processing face of the upper proximity head and a top surface of the substrate, and a second meniscus of processing liquid is generated between the processing face of the lower proximity head and a bottom surface of the substrate. The first meniscus has a meniscus protrusion extending in the linear direction in which the substrate is moved and positioned on a trailing side of the first meniscus relative to the linear direction in which the substrate is moved. The meniscus protrusion is centered on the substrate relative to a diameter of the substrate as measured perpendicular to the linear direction in which the substrate is moved.