Provided is a method of producing an epitaxial silicon wafer having high gettering capability resulting in even more reduced white spot defects in a back-illuminated solid-state imaging device. The method includes: a first step of irradiating a surface of a silicon wafer with cluster ions of CnHm (n=1 or 2, m=1, 2, 3, 4, or 5) generated using a Bernas ion source or an IHC ion source, thereby forming, in the silicon wafer, a modifying layer containing, as a solid solution, carbon and hydrogen that are constituent elements of the cluster ions; and a subsequent second step of forming a silicon epitaxial layer on the surface. In the first step, peaks of concentration profiles of carbon and hydrogen in the depth direction of the modifying layer are made to lie in a range of more than 150 nm and 2000 nm or less from the surface.