To improve the accuracy and the reproducibility of the thickness of a resist coated film by measuring the weight-change of a coated resist with the passage of time by using a measuring device which measures the weight of a wafer placed on a chuck continuously.

A discharge-quantity of a resist 8 on a wafer 9 is determined by increasing weight of a chuck 10 from the beginning of discharging to the end, namely, the increasing weight is input to a comparing-determining circuit 6 in which the difference between the increasing weight and the set weight is compared and processed, and then the discharge-quantity of the resist on the wafer 9 to be next treated are not changed when dripped quantities of the resist 8 are within 5% or less ± a standard value, and when they are above 5%, a correcting value is computed by a operating circuit 5 and a correcting value is directed to a discharge-quantity regulator 4, and an action is taken on a discharge pump 3 of the resist so that the discharge-quantity on the wafer 9 to be next treated is adjusted.