To provide a cleaning method with which generation of foreign matter can be extremely reduced when a substrate to be cleaned such as a transparent substrate for a photomask, a photomask blank, a photomask production intermediate, and a photomask, is cleaned, and provide a cleaning fluid supplying apparatus that supplies cleaning fluid to a cleaning apparatus.

In a cleaning method for cleaning a substrate to be cleaned by supplying cleaning fluid to a cleaning apparatus, when the cleaning fluid is filtered by a filtration filter for removing foreign matter and the filtered cleaning fluid is supplied to the cleaning apparatus through a supply pipe to clean the substrate to be cleaned, at least prior to supply of the filtered cleaning fluid to the cleaning apparatus, the filtered cleaning fluid is discharged to the outside of a system through a discharge pipe and then the filtered cleaning fluid is supplied to the cleaning apparatus through the supply pipe.