and is fixed under the reduced pressure and a plurality of wafers 5 are transferred at a time therefore the manufacturing cost of the transfer apparatus can be decreased and the size of the transfer apparatus is prevented from increasing in addition the generation of particles is suppressed so that wafers 5 can be transferred in a clean environment moreover simultaneous transfer of a plurality of wafers 5 improves the throughput and the capability of changing the pitch of wafers 5 makes it possible to change the pitch of wafers 5 so as to guarantee that wafer processing is performed highly accurately in the reaction chamber 70 in the present embodiment the walls 53 and 54 of the wafer transfer chamber 50 are opposed to each other so as to arrange on a substantially straight line the reaction chamber 70 the wafer transfer chamber 50 and the wafer accommodating chamber 30 and the wafer transfer chamber 50 has a rectangular shape as viewed from above as the wafer transfer chamber 50 has a rectangular shape the size of the wafer transfer chamber 50 can be reduced and the area occupied by the wafer transfer chamber 50 can be reduced accordingly thus the semiconductor wafer processing apparatus 1 occupies less area within a clean room by adopting the rectangular shape the cost of manufacture of the wafer transfer chamber 50 is reduced and a required maintenance space is also reduced further the distance over which a connection is made between the wafer transfer chamber 50 and another wafer transfer chamber or the like can be reduced this allows the wafers 5 to be readily transferred between the wafer.