Liquid chromatograph and column oven used therefor

A column oven for performing temperature control on a separation column in a liquid chromatograph, comprising:

• a gas sensor for detecting a vaporized gas of a solvent forming a mobile phase;
• a reference-threshold-value holding part for holding, as a reference threshold value Vtho, a threshold value determined from a detected value resulting from measurement by the gas sensor, for a vaporized gas of a certain solvent having a lower concentration than an explosive limit concentration;
• a calibration-factor holding part for preliminarily holding, as a device constant, a calibration factor Ge indicating a difference between sensitivities of the gas sensor to different solvents;
• a threshold-value calibration part for calculating a threshold value Vth from the reference threshold value Vtho held in the reference-threshold-value holding part and from the calibration factor Ge held in the calibration-factor holding part, according to
• Vth=Vtho×Ge,
• when a type of a solvent to be used is input;
• and
• a liquid leakage detection part for comparing a detected value from the gas sensor with the threshold value calculated by the threshold-value calibration part to detect a liquid leakage within the column oven, during use of the column oven.