Abstract: An apparatus for electrolytically processing aluminium material comprising rectifier means for supplying a pulse power to the electrodes, at least one of which is the aluminium material to be processed, and controller means for supplying a control signal to the rectifier means to enable the same to produce from a multi-phase AC power a pulse power balanced between the phases. The electrodes are connected with each other by a by-pass circuit which is controlled such that the electrodes are short-circuited by the by-pass circuit during the quiescent time of the pulse power to enable the electric charge stored in the electrolytic bath to be discharged rapidly to prevent the trailed natural discharge through the electrolytic path from interfering with the rise of the next pulse, thus preventing the deformation of the pulse waveform supplied to the electrodes.