Abstract: A photoresist discharge monitoring apparatus in which the photoresist discharge rate is monitored by a discharge pump, and based on this monitoring, the discharge pump is controlled, so that a constant photoresist discharge rate is ensured to prevent any occurrence of process defects due to the discharge pump. If the photoresist discharge rate is decreased due to the exhaustion of the life expectancy of the chemical filter, a filter replacement necessity is displayed. That is, a PR (photoresist) discharge rate sensor senses the photoresist discharge rate, the discharge rate being decided by the discharge pump. Further, a PR discharge rate controller monitors the output signals of the PR discharge rate sensor to automatically control the photoresist discharge rate of the discharge pump, and judges on a chemical filter replacement necessity upon the arrival of the operating limit in the step motor so as to output filter replacement signals.