A film formation apparatus includes a gas supply mechanism for supplying an aminosilane-based gas, and a silane-based gas that does not include an amino group. Processes of forming a seed layer on a surface of the insulation film having the opening reaching the conductive substance and on a bottom surface of the opening by supplying the aminosilane-based gas into the process chamber, and forming a silicon film on the seed layer by supplying the silane-based gas that does not include the amino group into the process chamber, are sequentially performed in the process chamber.