A method for cleaning a glass substrate containing SiO.sub.2 as a main
ingredient thereof ensuring removal of abrasive and foreign matter
adhered to the glass substrate after a polishing step, without
complicating a cleaning step, including a process in which the glass
substrate is cleaned by scrubbing using a liquid having Si element
stationary in a range from 1 to 5 000 ppb/mm.sup.2.