1. A processing apparatus comprising: a cassette rest unit configured to place thereon a cassette with a plurality of wafers housed therein; an unloading unit configured to unload a wafer from the cassette placed on said cassette rest unit; a feed unit configured to feed the wafer unloaded from the cassette by said unloading unit; a plurality of processing units disposed adjacent to said feed unit and configured to perform respective different processing processes on the wafer; and a control unit configured to control said cassette rest unit, said unloading unit, said feed unit, and said processing units; wherein the layout of said cassette rest unit, said unloading unit, said feed unit, and said processing units can be changed; said control unit includes a display panel for displaying an input screen for entering operating conditions for the units and memory means for storing at least the operating conditions for the units; said memory means includes an image memory for preparing in advance and storing respective plan-view images of the units; said display panel displays an overall apparatus map representing a combination of the plan-view images of the units as a layout of the processing apparatus in its entirety; and the layout of the plan-view images of the units in said overall apparatus map can be changed.