Processing method

A substrate processing method performed by a substrate processing apparatus comprising a processing chamber for performing therein a process on a processing target object by using a first processing gas and a second processing gas, which are different in at least one of a supply amount and a gas kind, a mounting table provided within the processing chamber and configured to mount thereon the processing target object, a processing gas discharge unit provided within the processing chamber to face the mounting table and configured to discharge the first processing gas and the second processing gas into the processing chamber, a space group that is provided within the processing gas discharge unit and partitioned by partition walls and includes a first space having a discharge hole through which the first processing gas is discharged, a second space having a discharge hole through which the second processing gas is discharged and at least one third space having a discharge hole through which a gas generated between the first space and the second space is discharged, a processing gas distribution unit including a processing gas distribution pipe group that includes a first processing gas distribution pipe communicating with the first space, a second processing gas distribution pipe communicating with the second space and at least one third processing gas distribution pipe communicating with the least one third space, a plurality of branch pipes that includes a first branch pipe connecting the first processing gas distribution pipe with the at least one third processing gas distribution pipe which is adjacent to the first processing gas distribution pipe and a second branch pipe connecting the second processing gas distribution pipe with the at least one third processing gas distribution pipe which is adjacent to the second processing gas distribution pipe and a valve group that includes a first valve opened or closed to the first processing gas distribution pipe and a second valve opened or closed to the second processing gas distribution pipe,

• wherein the substrate processing method comprises:
• switching, without mixing the first processing gas and the second processing gas, the gas discharged from the discharge hole included in the at least one third space by opening or closing the valve group.