The invention comprises a chamber (13) in which an object (11) is stored, a depressurizing pump (22) connected to the chamber (13) and depressuring the inside of the chamber (13), a microwave radiating means (12) radiating microwave to the object (11) in the chamber (13), an airflow generating means leading a gas from the outside into the chamber (13) to generate airflow in the chamber (13), and a control means (35) therefor. The object (11) in the chamber (13) is dried at a temperature less than the decomposing temperature of the object (11) by radiating on/off microwave in a depressurized state and in the state of generating airflow therearound. |