Provided is a substrate processing apparatus and a method of manufacturing a semiconductor device, which are hard to cause a defect in processing a substrate owing to that a pressure inside a process chamber is not kept constant, and which enable a better processing of a substrate. The channel housing is pivotally connected to a cam via a rivet or other pivot fastener at a pivot point. This invention is applicable to the absorption of shocks as well as to that of vibrations. Invalidation messages are sent to selected \u201cvictim\u201d clients on the client list, independent of whether the resource in question has changed, when the list meets a predetermined criterion, such as becoming too large.