To obtain treated squeezed lees hardly absorbing moisture, not fermented, capable of being preserved for a long period, and useful as a food extender, a fertilizer, a feed, a fuel, etc., by frying squeezed lees such as bean curd lees, sake (rice wine) lees or shochu (a Japanese distilled liquor) lees in specific conditions.

This method for treating squeezed lees comprises allowing the squeezed lees B fed from a tank 17 to pass through an oil bath 10 with a net conveyer 16 to fry the squeezed lees B with palm oil 11, etc., in the oil bath 10 at 130-200°C, drying the fried lees with a fan 12, and subsequently accumulating the treated squeezed lees C in a tank 21. The method enables to perfectly remove water from the squeezed lees B and coat the surfaces of the lees with the palm oil, etc., to substantially eliminate the hygroscopicity of the lees.