A method of polishing a substrate includes rotating a polishing table having a polishing surface, holding the substrate by a top ring, bringing the substrate into contact with the polishing surface while swinging and rotating the top ring to polish the substrate, and monitoring a surface condition of the substrate by a monitoring sensor. A rotational speed of the polishing table and conditions of swing motion of the top ring are determined such that a position of the monitoring sensor, a position of a center of rotation of the top ring, and a direction of the swing motion of the top ring at a point of time when a predetermined period of time has elapsed after polishing of the substrate is started approximately coincide with their previous values at a point of time before the predetermined period of time has elapsed.