To substantially reduce the time required for cooking rice and to double the period of time during which the taste and palatability of the cooked rice at the time of completion of cooking is retained in a very economical way by radiating infrared rays directly on the materials, water, etc., in cooking containers, and to make the process applicable to many foodstuffs other than rice as well.

Cooking containers with materials, water, etc., in them are conveyed to a heating device by a transporting device, and heating by this heating device is continued for a required period of time, and when the materials are cooked to an appropriate degree, the cooking containers are removed from the heating device by the transporting device for the contained cooked foodstuffs to be obtained. In this case, the cooking containers 1 which hold materials, water, etc., are made of infrared-transparent material and are so shaped that the materials inside may be immersed in water, etc., the transporting device 3 is power-driven, and the heating device consists in infrared emitters 7a, 7b which are placed in two or three or more directions relative to the cooking containers 1 conveyed by the transporting device 3, and which, when switched on, promptly radiate infrared rays on them.