A manufacturing method of an epitaxial silicon wafer includes: an epitaxial-film-growth step in which an epitaxial film is grown on a silicon wafer in a reaction container, and a temperature reduction step in which a temperature of the epitaxial silicon wafer is reduced from a temperature at which the epitaxial film is grown. In the temperature reduction step, a temperature reduction rate of the epitaxial silicon wafer is controlled to satisfy a relationship represented by R≦2.0×10-4X−2.9, where X (Ω·cm) represents a resistivity of the silicon wafer, and R (degrees C./min) represents the temperature reduction rate for lowing the temperature of the epitaxial silicon wafer from 500 degrees C. to 400 degrees C.