A film deposition apparatus has a vacuum chamber in which a turntable placing plural substrates is rotated, the plural substrates come into contact with plural reaction gases supplied to plural process areas and thin films are deposited on surfaces of the plural substrates, and has plural reaction gas supplying portions for supplying the plural processing gases, a separation gas supplying portion for supplying a separation gas and an evacuation mechanism for ejecting the plural processing gases and the separation gas, wherein the plural process areas includes a first process area for causing a first reaction gas to adsorb on the surfaces of the plural substrates, and a second process area, having an area larger than the first process area, for causing the first reaction gas having adsorbed the surfaces of the plural substrates and a second reaction gas to react, and depositing the films on the surfaces of the plural substrates.