An apparatus for controlling a water softener according to an exemplary embodiment of the present invention includes: a concentration detector detecting a concentration of total dissolved solids in water introduced into a channel; a voltage controller controlling a voltage applied to an electrode so that the detected concentration of the total dissolved solids reaches a target concentration; a flow rate detector detecting a flow rate of the water introduced into the channel; and a water softening time controller controlling, based on the detected flow rate, a water softening time for the water so that the detected concentration of the total dissolved solids reaches the target concentration.