The invention concerns a chromatographic device including a column (12) for receiving a chromatographic bed (14) through which flow a first fluid; a piston (36) sliding inside the column (12) an exerting pressure on the bed (14), a chamber (28) containing a second fluid exerting pressure on the piston (36); a regulator (52) for the pressure exerted by the piston (36) on the bed based on the pressure inside the chamber (28), on the flow pressure on the first fluid at the intake of the column (12) and on a reference pressure of the bed (14). Said device enables to separate at least two compounds to be subjected to chromatographic analysis, while adjusting the pressure exerted on the chromatographic bed. The device efficiently uses the chromatographic bed while protecting it.