A control system for a semiconductor substrate process line comprises a process line having processing units for processing a semiconductor wafer in accordance with preset data, a plurality of cassettes each for storing a plurality of semiconductor wafers and having an identification member on a surface thereof consisting of a plurality of projections arranged in a row, a non-contact type number reader provided at an entrance side of the processing unit for reading the cassette number designated by the identification member and generating a signal corresponding to the number, and a control unit in which processing conditions are input corresponding to the semiconductor wafers stored in the cassettes and which identifies the signal from the reader and controls the processing unit under processing conditions corresponding to the identified number.