PURPOSE: To obtain a resist film of high quality by providing an agitator, an ultrafine particle counter at a resist pipe and further a controller in parallel therebetween while dropping a resist from a nozzle on a semiconductor wafer placed on a wafer chuck and avoiding the influence of, if any, dusts and air bubbles.

CONSTITUTION: A semiconductor wafer 21 is placed on a rotatable wafer chuck 20, and a nozzle 22 which drops a resist is disposed oppositely to the wafer. A resist pipe 27 is connected with the nozzle 22, an agitator 23, an ultrafine particle counter 24, a pump 25 and a filter 26 are sequentially connected with the pipe, and a resist vessel 29 is provided at the end, and a controller 28 is further connected in parallel between the agitator 23 and the counter 24. Thus, a coating apparatus is constructed, the number of dusts in the resist liquid is always detected by the counter 24. When the numbers of the dusts and air bubbles exceed the prescribed numbers, the counter 24 applies a signal to the controller 28 to operate the agitator 23 and to displace the position of the nozzle 2 out of dropping.