To provide a semiconductor manufacturing equipment control method which is capable of keeping data as to the state of equipment units stored in a host computer in matching with the actual state of equipment units, accurately controlling the equipment units through the host computer, accurately controlling the overall production record of the facilities, and changing the state of equipment units even through an indirect computational operation made through the host computer.

When a prescribed state change item occurs in equipment units, following four steps are successively carried out, a step 10 in which data (real data) as to the actual state of the equipment units are received from the equipment units, a step 20 in which the stored data corresponding to a unit out of data as to the state of units stored in a data base are searched first, a step 30 where it is discriminated whether a prescribed change item is present or not by comparing the real data with stored data, and a step 40 in which real data are continuously received when it is found that no prescribed change item is present in real data, and the content of the stored data is first updated in accordance with the content of real data when it is found that a prescribed change item is present in real data.