PURPOSE: To dry a sol-like material with high efficiency in a short time by cooling the sol-like material to obtain its gel, and irradiating the obtained gel with far IR.

CONSTITUTION: A raw sol 1 as a sheet-shaped food raw material made from carrot consisting of high molecular polysaccharides, condiments, and about 85% water is supplied to a tank 2 to coat a circulating belt conveyor 3 with the sol 1 at a coating part 4. In this case, the sol 1 is heated to 70°C and then cooled to 40°C by a cold air fan 5 to convert the sol into a gel-like sheet. The gel-like sheet is introduced into a far IR furnace in which a far IR heater 6 is provided and heated air at 90°C is circulated, heated for 10min, dried, and wound in a winding part 8 to obtain a product 9. Namely, since the irradiation by far IR is carried out without the energy density being lowered, the sol is dried with high efficiency in a short time.