PURPOSE: To make passible replenishment while maintaining the ratios of the respective liquids of replenishing liquids at specified ratios as far as possible without adjusting the discharge rate of pumps each time by executing the replenishment by dividing the other replenishing liquid before the replenishment with the replenishing liquid having the max. replenishing time ends.

CONSTITUTION: For example, the replenishing amt. of a developer is assumed to be 4L and the replenishing amt. of water to be 1L and the developer is assumed to be subjected to oxidation replenishment with lapse of time (ratio 4:1). The replenishing time for 4L developer is 1000 seconds if the discharge rate of the pumps to be used at this time is adjusted to 120cc/30sec for both of the developing pump and the water pump. The developer is replenished with the water dividedly within this replenishing time. The time to end the divided replenishment is preferably the same as the time (1000 seconds in this case) to end replenishment with the replenishing liquid which is not dividedly replenished, i.e. the replenishing liquid (the developer in this case) having the max. replenishing time. The number of divisions of the divided replenishment may be arbitrarily selected and the ratio is more approximate to the specified value as the replenishment is more finely divided.