PURPOSE: A distillation column including spaces divided by dividing walls is provided to be easily driven by obtaining uniform a pressure dropping phenomenon between two divisional regions. CONSTITUTION: A main column includes a dividing wall(51). A pressure-standardization unit for a pre-divisional region and a main-divisional region is installed to the main column. The pressure-standardization unit is either of a collector tray(C) or a dividing wall which is spaced apart from a lowermost tray. A nozzle with 10 to 30mm of a size is formed to the collector tray.
