A replenisher supplying apparatus includes a plurality of cartridges, a plurality of stock tanks, a plurality of supply devices for supplying the component agents stored in the stock tanks to a processing tank, communication devices for supplying the component agents filled in the cartridges to the stock tanks, detection devices for detecting whether the quantity of each of the component agents stored in the stock tanks has decreased to be equal to or less than a predetermined level, and a control device for operating, at a time when it is judged by the detection devices that the quantity of a component agent stored in one of the stock tanks has decreased to be equal to or less than the predetermined level, and operating one of said supply devices so as to reduce the quantity of a component agent stored in another stock tank to a level equal to or less than the predetermined level, and operating said communication devices so as to supply the component agents to the stock tanks. Since the plural cartridges can be exchanged at one time, the frequency of exchange operation of the cartridges can be reduced, whereby work efficiency is increased.