A film deposition apparatus is provided with a gas nozzle in which ejection holes that eject a reaction gas are formed along a longitudinal direction of the gas nozzle, and a flow regulation member that protrudes from the gas nozzle in either one of upstream and downstream directions of a rotation direction of a turntable. In such a configuration, a separation gas flowing from an upstream side of the rotation direction to the gas nozzle is restricted from flowing between the gas nozzle and the turntable on which a substrate is placed, and the reaction gas flowing upward from the turntable is restricted by the separation gas, thereby impeding a reaction gas concentration in a process area from being lowered.