To eliminate a defect that much time is needed when an IC package is dried for regeneration by using an ordinary temperature low humidity chamber.

In an IC package dehumidifying device, a heating means is situated in a low humidity chamber. The low humidity chamber comprises a dry unit containing a drying agent and a drying agent heater and an opening and closing means to switch atmosphere in the dry unit to the interior of the low humidity chamber and the outside of the chamber for communication. The heating means is situated at the inner lower part of the low humidity chamber. The interior of the low humidity chamber is maintained approximately at 40°C.