Apparatus for the surface electrolytic treatment in continuous of metal semi-finished products, in particular flat metal semi-finished products, comprising: - a containment tank containing an electrolytic solution and inside which a metal semi-finished product is made to advance in continuous along an advancement plane, - immersion means (31, 32, 33) for immersing said metal semi-finished product into said electrolytic solution, - at least one pair of electrodes opposite to each other and between which said metal semi-finished product is made to advance in continuous, wherein said pair of electrodes comprises at least one first electrode facing one of the two opposite plane faces of said advancement plane and at a defined distance from said semi-finished product so as to define with it a first interspace and at least one second electrode facing the other one of said two opposite plane faces of said advancement plane and at a defined distance from said semi-finished product so as to define with it a second interspace and wherein said at least one pair of electrodes is immersed in said electrolytic solution and is associable with an electric power supply group, - inletting and agitation means for inletting and agitating said electrolytic solution in said tank, characterised in that - said inletting and agitation means comprise at least one duct arranged at said at least one pair of electrodes and provided with a delivery end facing one of said two opposite plane faces at respectively said first interspace or said second interspace and with a suction end that is opposite to said delivery end and open and immersed in the electrolytic solution contained in said tank, and at least one inletting nozzle for inletting said electrolytic solution which is associable with feeding means of said electrolytic solution and the outlet mouth of which is arranged at said suction end of said at least one duct, wherein said suction end of said at least one duct has a portion that is free from said at least one nozzle and that is immersed in the electrolytic solution contained in said tank and wherein the jet of electrolytic solution emitted by said at least one nozzle draws, from the inside of said tank, an electrolytic solution current that enters said at least one duct through said suction end portion, said jet and said current mixed together exiting from said delivery end at said first interspace or said second interspace. - a containment tank containing an electrolytic solution and inside which a metal semi-finished product is made to advance in continuous along an advancement plane, - immersion means (31, 32, 33) for immersing said metal semi-finished product into said electrolytic solution, - at least one pair of electrodes opposite to each other and between which said metal semi-finished product is made to advance in continuous, wherein said pair of electrodes comprises at least one first electrode facing one of the two opposite plane faces of said advancement plane and at a defined distance from said semi-finished product so as to define with it a first interspace and at least one second electrode facing the other one of said two opposite plane faces of said advancement plane and at a defined distance from said semi-finished product so as to define with it a second interspace and wherein said at least one pair of electrodes is immersed in said electrolytic solution and is associable with an electric power supply group, - inletting and agitation means for inletting and agitating said electrolytic solution in said tank, characterised in that - said inletting and agitation means comprise at least one duct arranged at said at least one pair of electrodes and provided with a delivery end facing one of said two opposite plane faces at respectively said first interspace or said second interspace and with a suction end that is opposite to said delivery end and open and immersed in the electrolytic solution contained in said tank, and at least one inletting nozzle for inletting said electrolytic solution which is associable with feeding means of said electrolytic solution and the outlet mouth of which is arranged at said suction end of said at least one duct, wherein said suction end of said at least one duct has a portion that is free from said at least one nozzle and that is immersed in the electrolytic solution contained in said tank and wherein the jet of electrolytic solution emitted by said at least one nozzle draws, from the inside of said tank, an electrolytic solution current that enters said at least one duct through said suction end portion, said jet and said current mixed together exiting from said delivery end at said first interspace or said second interspace.