PURPOSE: To obtain satisfactory steamed grains to have a swelling by providing a steam blowing-in tube in a water tank part in the lower part of a vessel main body and heating saturated steam, which is generated by being blown into water, with a steam heater.

CONSTITUTION: When the steam is blown from the blowing-out hole of a steam blowing-in tube 6 into the water of a water tank 5, this steam is cleaned by the water and iron content is removed. Then, the steam goes over an internal wall 4 in the condition of the saturated steam, flows from an upper direction into an inner cylinder part 7 and goes up through a heating tube 13 of a steam heater 8. After that, the steam passes through a central hole 9a' of a crosspiece board receiving stand 9 and a steam passing hole 10a and steams raw material rice 32. A temperature in such a case is 98-100°C and time is 30-40 minutes. After a steaming process, the blowing-in of the steam is continued from the steam blowing-in tube 6 and heating steam is sent through a heating steam tube 18 to the steam heater 8. Then, the saturated steam to pass through the steam heater 8 and the steamed raw material rice 32 is heated for 10-15 minutes at 102-103°C.