A substrate cleaning method includes removing a foreign material attached to a substrate while preventing deterioration of the substrate and any film formed on or above the substrate. A cleaning gas at a pressure between 0.3 MPa and 2.0 MPa is sprayed towards a wafer W with attached foreign material 22 placed in a near-vacuum, producing clusters 21 made up of a multitude of gas molecules 20, and the clusters 21 collide with the wafer W without undergoing ionization.