PURPOSE: To efficiently recover a dried onion in a white state by dehydrating moisture of finely cut small pieces, then passing the small pieces between a pair of heated drums having the same diameter, hot-pressing the small pieces and peeling the hot-pressed small pieces from the drums.

CONSTITUTION: Root and neck parts of an onion are cut and browned exodermises are removed. The resultant onion is then finely cut to 3-5mm size with a chopper, etc., and dehydrated. The obtained raw material is subsequently charged from a hopper 3 into a dryer 2 with a conveyor 1. Steam is fed from a boiler 8 through a pipe 11 into the interior of drums 5 in the dryer 2 and the drum surface temperature is preferably heated to 160-165°C. The raw material small pieces finely cut between the pair of heated drums are hot-pressed, thermally adhered to the drum surfaces, rotated, then scraped off with scrapers 19 and collected into containers 6 to afford the objective dried onion.