PURPOSE: To accurately replenish a processing soln. by controlling the time to stop a processing soln. replenishing means based on the number of pulses corresponding to the amt. of the soln. to be replenished.

CONSTITUTION: The amt. of the processing soln. to be supplied to a processing soln. tank is detected by a supply detecting means 90 consisting of a flow rate sensor, etc., and the detection signal is supplied to a pulse generating means 92. The pulses are successively generated by the means 92 at regular time intervals in accordance with the detected amt., and supplied to a control means 94 and a measuring means 96. The unreplenished amt. of the soln. not replenished at the preceding time, etc., are stored in a storage means 98, and the number of pulses stored in the means 98 is added to the number of pulses corresponding to the calculated amt. of the soln. to be replenished at the next time by an arithmetic means 100. The time to stop pumps 171... is controlled by the means 94 consisting of a CPU, etc., based on the number of pulses.