Column oven and chromatography

A column oven comprising:

• a hollow housing;
• an analysis column arranged in the hollow housing and along a vertical direction and allowing circulation of a mobile phase in the analysis column;
• a heating portion configured to heat air;
• a holding portion configured to hold the analysis column along the vertical direction;
• a swirl flow generation portion arranged at an upper end side of the analysis column and configured to discharge, as a swirl flow, the air heated by the heating portion into the hollow housing;
• and
• a throttle portion arranged at the upper end side of the analysis column and configured to throttle the swirl flow when the swirl flow is discharged into the hollow housing,
• wherein the swirl flow generation portion and the throttle portion are arranged only in an upper end side of the analysis column,
• a suction port arranged at a lower end side of the analysis column and to suck an air in the hollow housing into a space where the heating portion is arranged without swirl flow generation occurring at the suction port, and
• the throttle portion has multiple through-holes formed to penetrate the throttle portion along a direction of discharging the swirl flow and arranged in a honeycomb shape as viewed from a swirl flow discharge side.