The present invention provides a chamber 1 comprising a chamber section 2 having a substrate processing compartment into which a substrate is loaded for a predetermined processing step, and reinforcing members 3 removably mounted on the discrete outer walls of the chamber section. Each of the reinforcing members comprises a plate-like joint member 32 or a rib member 31 which is removably mounted on the corresponding outer wall of the chamber section. The reinforcing member may comprise both the plate-like joint member 32 and rib member 31.