A processing apparatus capable of changing at least one of a supply amount and a kind of a processing gas that is discharged to a processing target object depending on a position in a surface of the processing target object, the processing apparatus comprising: a processing chamber for performing therein a process on the processing target object by using the processing gas; a mounting table provided within the processing chamber, for mounting thereon the processing target object; a processing gas discharge unit provided within the processing chamber so as to face the mounting table and configured to discharge the processing gas into the processing chamber; a space group that is provided within the processing gas discharge unit and partitioned by partition walls, and that includes a first space corresponding to a central portion in the surface of the processing target object, a second space corresponding to an edge portion in the surface of the processing target object and at least one third space (15b-15h) between the first space and the second space, the first to the third spaces (15a-15i) being provided with discharge holes through which the processing gas is discharged; a processing gas distribution unit including: a processing gas distribution pipe group that includes processing gas distribution pipes (18a-18i) communicating with the first space, the second space and the at least one third space (15b-15h); and a valve group that includes valves (19a-19h) provided between adjacent processing gas distribution pipes (18a-18i), respectively; the processing apparatus further comprising: a controller configured to control the valves (19a-19h) to be opened or closed to allow adjacent processing gas distribution pipes (18a-18i) to communicate with each other or be isolated from each other, wherein a first processing gas main supply pipe is connected with a first processing gas distribution pipe, which belongs to the processing gas distribution pipes (18a-18i) and which is arranged to communicate with the first space, and a second processing gas main supply pipe is connected with a second processing gas distribution pipe, which belongs to the processing gas distribution pipes (18a-18i) and which is arranged to communicate with the second space. a processing chamber for performing therein a process on the processing target object by using the processing gas; a mounting table provided within the processing chamber, for mounting thereon the processing target object; a processing gas discharge unit provided within the processing chamber so as to face the mounting table and configured to discharge the processing gas into the processing chamber; a space group that is provided within the processing gas discharge unit and partitioned by partition walls, and that includes a first space corresponding to a central portion in the surface of the processing target object, a second space corresponding to an edge portion in the surface of the processing target object and at least one third space (15b-15h) between the first space and the second space, the first to the third spaces (15a-15i) being provided with discharge holes through which the processing gas is discharged; a processing gas distribution unit including: a processing gas distribution pipe group that includes processing gas distribution pipes (18a-18i) communicating with the first space, the second space and the at least one third space (15b-15h); and a valve group that includes valves (19a-19h) provided between adjacent processing gas distribution pipes (18a-18i), respectively; a processing gas distribution pipe group that includes processing gas distribution pipes (18a-18i) communicating with the first space, the second space and the at least one third space (15b-15h); and a valve group that includes valves (19a-19h) provided between adjacent processing gas distribution pipes (18a-18i), respectively; a controller configured to control the valves (19a-19h) to be opened or closed to allow adjacent processing gas distribution pipes (18a-18i) to communicate with each other or be isolated from each other, wherein a first processing gas main supply pipe is connected with a first processing gas distribution pipe, which belongs to the processing gas distribution pipes (18a-18i) and which is arranged to communicate with the first space, and a second processing gas main supply pipe is connected with a second processing gas distribution pipe, which belongs to the processing gas distribution pipes (18a-18i) and which is arranged to communicate with the second space.