To provide a processing device that reduces flexure of a straightening wall disposed around a workpiece.

In the processing device 2 for carrying out, for example, etching of the workpiece S disposed on a placement table 3 by supplying a processing gas into a processing chamber 20, a straightening member 5 connects a plurality of the straightening walls 51 extending along each side of the workpiece S so that the workpiece S is enclosed. Both end portions of each straightening wall 51 are supported by a supporting member 52, and the upper limb thereof is gradually formed high in a direction of a center of the straightening wall 51 while a lower limb thereof is formed parallel to an upper surface of the placement table.