A plating apparatus can keep concentrations of components of a plating solution constant over a long period of time and can stably form a plated film having a more uniform thickness on a surface of a substrate while minimizing an amount of the plating solution used. The plating apparatus includes a plating cell for carrying out electroplating of a surface of a substrate with a space between the surface of the substrate, serving as a cathode, and an insoluble anode filled with a plating solution, a plating solution circulation system for supplying the plating solution to the plating cell and recovering the plating solution in a circulatory manner, and a plating solution component replenishment system for supplying a replenisher solution, containing a component of the plating solution in a higher concentration than that in the plating solution, to the plating solution which circulates in the plating solution circulation system, thereby maintaining the concentration of the component in the plating solution within a predetermined range.