An object of the invention is to avoid an inconvenience at a connection portion formed by filling a metal film in a connecting hole, which has been opened in an insulating film, via a barrier metal film having a titanium nitride film stacked over a titanium film. A manufacturing method of a semiconductor device has the steps of: forming a thermal reaction Ti film over the bottom of a connecting hole by a thermal reaction using a TiCl4 gas; forming a plasma reaction Ti film by a plasma reaction using a TiCl4 gas; forming a nitrogen-rich TiN film over the surface of the plasma reaction Ti film by plasma treatment with H2 and plasma treatment with NH3 gases; repeatedly carrying out film formation by CVD using a WF6 gas and reduction using an SiH4 or B2H6 gas to form a tungsten nucleation film of a multilayer structure over the nitrogen-rich TiN film; and forming a blanket•tungsten film at 400° C. or less by CVD using WF6 and H2 gases. This makes it possible to avoid an inconvenience at a connection portion formed by filling a metal film in a connecting hole, which has been opened in an insulating film, via a barrier metal film having a titanium nitride film stacked over a titanium film.