An autosampler for a liquid chromatograph having temperature control modes of cooling temperature control and heating temperature control, comprising: a temperature control space for containing a sample and controlling a temperature of the sample; an air temperature control part having an air intake portion for sucking in air from the temperature control space, a fan for blowing air taken in from the air intake portion toward the sample contained in the temperature control space, a first temperature control element provided for performing at least cooling of air taken in from the air intake portion on a path of the air, and a second temperature control element that is driven independently of the first temperature control element and provided to perform at least heating of air taken in from the air intake portion downstream of the first temperature control element on a path of the air; and a temperature control part configured to control operation of the air temperature control part to adjust a temperature in the temperature control space, wherein the temperature control part is programmed to cause the air temperature control part to perform cooling temperature control operation to lower the temperature in the temperature control space to lower than room temperature when the temperature control mode is the cooling temperature control, and is programmed to cause the air temperature control part to perform heating temperature control operation to raise the temperature in the temperature control space to higher than room temperature when the temperature control mode is the heating temperature control, and the temperature control part is programmed to cause the air temperature control part to perform dehumidifying heating operation in at least part of a process of raising the temperature in the temperature control space lower than room temperature after the temperature control mode is switched from the cooling temperature control to the heating temperature control, wherein the dehumidifying heating operation is for cooling and dehumidifying air taken in from the air intake portion with the first temperature control element and heating air dehumidified by the first temperature control element with the second temperature control element. a temperature control space for containing a sample and controlling a temperature of the sample; an air temperature control part having an air intake portion for sucking in air from the temperature control space, a fan for blowing air taken in from the air intake portion toward the sample contained in the temperature control space, a first temperature control element provided for performing at least cooling of air taken in from the air intake portion on a path of the air, and a second temperature control element that is driven independently of the first temperature control element and provided to perform at least heating of air taken in from the air intake portion downstream of the first temperature control element on a path of the air; and a temperature control part configured to control operation of the air temperature control part to adjust a temperature in the temperature control space, wherein the temperature control part is programmed to cause the air temperature control part to perform cooling temperature control operation to lower the temperature in the temperature control space to lower than room temperature when the temperature control mode is the cooling temperature control, and is programmed to cause the air temperature control part to perform heating temperature control operation to raise the temperature in the temperature control space to higher than room temperature when the temperature control mode is the heating temperature control, and the temperature control part is programmed to cause the air temperature control part to perform dehumidifying heating operation in at least part of a process of raising the temperature in the temperature control space lower than room temperature after the temperature control mode is switched from the cooling temperature control to the heating temperature control, wherein the dehumidifying heating operation is for cooling and dehumidifying air taken in from the air intake portion with the first temperature control element and heating air dehumidified by the first temperature control element with the second temperature control element.