To make it possible to prevent the generation of saprophytic bacteria on the inside walls of a tank for washing cereals and to ensure the hygienic execution of washing of the cereals and the cooking of rice with a cereal washing device used for an automatic rice cooking device, or the like, by installing a sterilizing means for irradiating the inside of the tank with UV rays.

The automatic rice cooking device 2 is equipped with a rice storage house, a washing section and a rice cooking section successively from an upper side. This storage house is internally equipped with a hopper 7, and a rice feeder 9 is disposed at a communication path 19 communicating with this communication port 18 of a top plate 17. The washing section is mounted with the tank 1 at the rear surface of the top plate 17 and an agitating device 10 is disposed at the inner center thereof. An adjusting plate 26 is disposed in an overflow port 24 in the upper part. The inside walls of the tank 1, the rear surface of the top plate 17 and the overflow adjusting plate 26, or the like, are respectively coated with materials having a photocatalyst effect. In such a case, a sterilizing lamp 27 for irradiating the tank with the UV rays is installed to the rear surface of the top plate 17 to irradiate the inside wall of the tank 1 with the UV rays and to sterilize the tank.