A processing unit including a supply section for storing a mask having a patterned surface having a pattern to be exposed to a plate, the supply section being maintained under atmospheric pressure, a process chamber for processing the plate, the process chamber being maintained in a reduced pressure or vacuum atmosphere and the processing unit transferring the mask between the supply section and the process chamber, and a protection unit for protecting the patterned surface in a non-contact manner and for holding part of the mask other than the patterned surface. The protection unit covers the mask while opening at least a part of the other side surface of the patterned surface. The processing unit further includes a transfer unit for adsorbing the protection unit and for transferring the protection unit and the mask held by the protection unit, between the supply section and the process chamber.