Abstract: An insulating spacer 30 comprises a plurality of unit spacers 40, and a flexible coupling portion 41 for coupling the unit spacers 40 along the axial direction thereof, wherein the unit spacer 40 comprises a plurality of annular plates 42 and 43 each having an insertion hole 44 for inserting the auxiliary anode 11, and a coupling frame 45 for coupling the annular plates 42 and 43 in the axial direction of the auxiliary anode 11 while opening the outer circumference side thereof. The auxiliary anode unit 10 is constituted by inserting the insulating spacer 30 into the auxiliary anode 11, and since each unit spacer 40 is coupled, the distal end of the auxiliary anode 11 is naturally located in proximity to the insertion hole 44 provided in the next unit spacer 40 when the auxiliary anode 11 penetrates one unit spacer 40. Accordingly, the auxiliary anode 11 can be inserted into the insulating spacer 30 by series of works, and as a result, the auxiliary anode unit 10 can be manufactured with good workability.

Abstract: A flexible auxiliary anode element for electroplating a tubular workpiece while the workpiece and an anode element are immersed in a plating liquid contained in a plating both. The flexible auxiliary anode element can be inserted into a hollow interior of the workpiece so that a metal wire of the auxiliary anode element is insulated from an inner peripheral surface of the workpiece by an insulating spacer.