Abstract: A dehumidification device according to the present invention includes an operation control unit configured to switch between thermo-on for circulating refrigerant in a refrigerant circuit and thermo-off for suspending circulation of the refrigerant, and an operation mode control unit configured to switch an operation mode to any one of a first operation mode in which a moisture adsorption unit is caused to adsorb moisture and a second operation mode in which moisture retained in the moisture adsorption unit is caused to be desorbed. The operation mode control unit is configured to select the operation mode at a time when the thermo-on is switched from the thermo-off in response to the operation mode and a relative humidity of air in switching from the thermo-on to the thermo-off.