PURPOSE: To prepare a liquid chromatographic column high in separation performance with good reproductivity, by driving a pump for feeding a packing liquid in accordance with the time program of flow rate and pressure preset in a control mechanism.

CONSTITUTION: A control unit 2 for controlling a pump 1 is equipped with a microcomputer unit, and sets a proper program by operating keys to start a device. A packing liquid in its storage tank 6 is fed to a packer 7 in accordance with the program with a pump 1. A gel slurry in the packer 7 is moved into the column 8 to automatically form a dense gel gradually. Sequential operations from the feed of the gel slurry to the control of packing density are automatically controlled. The reproductivity of the column is improved by fixing the packer 7 and the column 8 in a thermostat 9 and maintaining temp. of the packing liquid constant. Trouble due to bubbles produced in the pump 1 is prevented by removing a gas dissolved in the packing liquid in a degassing unit 5.