To provide an all-purpose distillation device capable of both continuous distillation and batch distillation easily and inexpensively by mounting an overflow tube and a pressure equalizing tube on the bottom flask of a boiling tower and performing atmospheric distillation or vacuum distillation utilizing the batch and continuous methods.

An overflow tube 16 is mounted on a tower bottom flask 13 to keep the liquid level in the tower bottom flask 13 fixedly through a three-way cock 15. At this time, the pressure in the tower bottom flask 13 and that of a bottom product receiving vessel 21 are kept to be same through a pressure equalizing tube 18 so as to prevent all the liquid in the tower bottom flask 13 from escaping down to the bottom product receiving vessel 21. And a warm water condenser 17 is mounted on the way of the pressure equalizing tube 18 so as to prevent the vapor in the tower bottom flask 13 from flowing through the pressure equalizing tube 18 to the bottom product receiving vessel 21. Further, a distillation column 5 provided with a heat insulating tube 6 wound with a heater 7 is unitized and the number of the distillation columns 5 used is increased or reduced in accordance with the resolution of the distillation. And the liquid level in the bottom flask 13 is varied by changing the lengths of the tubes 16 and 18.