A substrate cleaning method includes: a first step in which a cleaning liquid is ejected from a nozzle N2 to a central portion of a wafer W; a second step in which a dry gas is ejected from a nozzle N3 to the central portion of the wafer W to form a dry area; a third step in which the cleaning liquid is ejected from the nozzle N2 while the nozzle N2 is moved from a central side of the wafer W to a peripheral side thereof; a fourth step in which a width of an intermediate area generated between a wet area and the dry area is acquired; and a fifth step in which, when the width of the intermediate area exceeds a predetermined threshold value, a process parameter is changed such that the width of the intermediate area becomes the threshold value or less.