PURPOSE: To carry out the subject drying by using the subject drying device having a far- infrared rays-radiating ceramic layer on the surface of the inside wall, a heater in the inside thereof and further a vacuum pump and placing a vessel containing a processed flower, a processed insect, etc., buried in powder and granules consisting of far infrared rays-radiating ceramics, etc., in the above-mentioned device.

CONSTITUTION: The subject drying device 10 constituted of an oven 11 containing a far infrared rays-radiating ceramics layer 14 on the surface of the inside wall and a heater 15 in the inside thereof and a vacuum pump 12 is initially prepared. A processed material 17 of a flower, an insect, etc., is then put into a vessel 16 such as a glass beaker and powder and granules 18 consisting of far infrared rays-radiating ceramics are put thereinto to bury the processed material 17. The resultant processed material-containing vessel is placed in the above-mentioned device and the inside of the oven is kept at ≤30mmHg and 40-60°C, thus carrying out the subject drying. Silica gel may be used as the above-mentioned powder and particles and usage of a mixture of silica gel and ceramics has an advantage such that drying rate is controllable. The above-mentioned drying method does not cause partial overdrying because of the relatively low operating temperature and has a resistance to breakage of the processed material in case of using a microballoon or a porous body as the above- mentioned powder and granules.