An apparatus and method for cathodic protection in an environment where thin film corrosive fluids are formed is provided. The apparatus which protects from corrosion an object exposed to the thin film corrosive fluids, by artificially adjusting a potential of the object, comprises a DC power supply of which cathode is electrically connected to the object to be corrosion-protected, and an anodic assembly of which anode is electrically connected to the DC power supply. The anodic assembly includes an insulating filter member through which the corrosive fluids pass and which forms an accommodation space inside the insulating filter member, an anodic member accommodated in the insulating filter member, an electrode lead line which electrically connects the DC power supply to the anodic member, and an absorption conductive member which is accommodated in the insulating filter member to surround the circumference of the anodic member and absorbs the corrosive fluids flowing along an exposed surface of the object to be corrosion-protected.