PURPOSE: To prepare a raw material for high-quality dried small sardines and flakes of dried bonito with a small amount of fuel consumed in a short preparation time, by keeping a chamber having fishing at specific high temperature and high pressure, reducing the pressure so that water in the fishes are taken out, drying them with hot air.

CONSTITUTION: Fishes as a raw material are put in a drying chamber, and high-temperature pressurized steam at 100W130°C at 1.2W1.8atm is sent to the chamber for 10W 30min. In this process, the fishes are steamed, and water in them is converted into steam and eliminated. The feed of the high-temperature pressurized air is stopped, the chamber is evacuated by a vacuum pump, etc., steam and water in the fishes are enforcedly discharged. The evacuation and reduction in pressure of the chamber is continued for 1W3hr. The evacuation in reduced pressure is stopped, hot air is introduced into the chamber for 7W15hr, usually 10hr so that the fishes are mildly dried. By the above-mentioned method, the preparation time for dried small sardines and flakes of dried bonito can be shortened to approximately 1/3, and an amount of fuel consumed can be reduced about by one half. The product has high quality because the excess oil component is extracted from it and deterioration in quality will not occur.