There is provided a Cu wiring forming method for forming a Cu wiring by filling Cu in a recess, which is formed in a predetermined pattern in a Si-containing film of a substrate. The Cu wiring forming method includes forming a Mn film, which becomes a self-aligned barrier film by reaction with an underlying base, at least on a surface of the recess by chemical vapor deposition, forming a Cu film by a physical vapor deposition to fill the recess with the Cu film, and forming a Cu wiring in the recess by polishing the entire surface of the substrate by a chemical mechanical polishing.