Abstract: An object in the present invention is to provide a column oven capable of maintaining excellent temperature stability despite ambient temperature changes around the column oven. A column oven 10 has an outer chamber 12, an inner chamber 14 disposed in the outer chamber 12, and column 16 disposed in the inner chamber 14. The outer chamber includes heater 18, fan 20 for the outer chamber for circulating air heated by the heater 18, and a temperature sensor 22 for the outer chamber for detecting temperature inside the outer chamber. The inner chamber 14 includes fans 24 for the inner chamber and a temperature sensor 26 for the inner chamber for detecting temperature inside the inner chamber. An inner chamber wall is spaced-apart from an outer chamber wall. A target temperature in the outer chamber is set based on temperature detected by the temperature sensor 26 for the inner chamber.