To improve the quality of the electrodeposited surface and to effectively utilize electric power by applying a current in the reverse direction and then stopping the power supply for a fixed time before the supply direction is reversed to the forward direction.

The power supply is temporarily stopped between the current application in the reverse direction and that in the forward direction, an effective new additive is adsorbed on the surface of a cathode by utilizing the natural convection on the cathode surface, and the suspended copper powder is allowed to flow away from the vicinity of the cathode surface. Meanwhile, although the time necessary for the discharge of a charged layer on the electrode surface is 30sec at a minimum, the additive is not readsorbed since the cathode surface is in the state of a positive electrode due to the reverse current as long as the charged layer exists. Accordingly, the actual power stopping time is controlled to 30-100sec. When the power is stopped for ≥100sec, the effective current efficiency for the electrolyzing time is lowered. The passivation of the anode is strictly prevented by reversing the current at least once in 15-1hr.