PURPOSE: To obtain KOJI of desired quality continuously, by circulating steamed rice on parallel belt conveyors, tilted in the opposite directions, and connected with screw feeders mutually at the ends thereof in a sealed casing.

CONSTITUTION: An apparatus for producing KOJI capable of opening a door 25 of an inlet 26, pushing a rotating plate 24 down to the inlet 26, supplying the fed steamed rice to a frame body 19, feeding the steamed rice to the end on the lower side of a conveyor 6 by a screw shaft 20 rotated by a motor, dropping the steamed rice from openings of the frame body 19 onto the conveyor 6, moving the steamed rice on the conveyor 6 at about 1m/min speed, dropping the steamed rice from the end 31 at a high level on the lower end of a conveyor 5, parallel to the conveyor 6, and tilted in the opposite directon by a screw shaft 32 rotated by a motor 33, and circulating the steamed rice from the conveyor 5 to the conveyor 6. The conversion of the steamed rice into KOJI is adjusted by a CO2 sensor 43, temperature sensor 44, humidity sensor 45 and material temperature sensor, and a door 28, outlet 29 and rotating plate 27 are opened when the KOJI is grown to give a desired quality, and a slide plate 30 is pushed into the bottom of the frame body 19 to take out the resultant KOJI.