Copper electroplating was performed in an acid copper sulfate plating bath with polyethylene glycol, sulfopropyl disulfide, and Cl- (HCl). In order to remove accelerator from the plating surface, reverse pulses were applied during the electroplating. After reverse pulse, suppression recovery was obtained with solution agitation while significant acceleration was observed in a stagnant bath. It was found that accumulated accelerator could be removed by reverse pulses with solution agitation, and leveling of copper deposit on a patterned chip was demonstrated by applying reverse pulses during the electroplating. In a stagnant accelerator free bath, suppression weakening was observed after reverse pulse. It was suggested that copper chloride, which may be formed by the reverse pulse, attracts accelerator adsorption. Therefore, it is conceivable that significant acceleration in the stagnant bath is caused by mixed effect of the suppression weakening and the attraction of accelerator by the copper chloride.