In the semiconductor integrated circuit device lithography process it is becoming more and more essential to control both exposure dose and focus value independently with a high accuracy. Using a wafer treated precedingly, a section profile of a photoresist is acquired by the technique of scatterometry, then both exposure dose and focus value are estimated independently with a high accuracy on the basis of the section profile thus acquired and using a conjectural expression obtained by the technique of multivariate analysis, and a focus setting in the exposure of a succeedingly treated wafer is corrected on the basis of the estimated exposure dose and focus value.