PURPOSE: To obtain dried grains of good quality and to prevent the blocking of a primary air flowing through an airflow dust, by mounting a blast duct, incorporating a blower, outside the airflow duct.

CONSTITUTION: A gasifying burner is installed in an airflow duct 9. A blast duct 12 incorporating a blower 33 is installed in a position beneath a lower wall 32 of the airflow duct 9. A small size part 14 is located in a manner to project upward from an upper end, at an upstream side 13 of the blast duct 12. A motor 16 is mounted to the lower part at the upstream side 13 of the blast duct 12, and a rotary shaft 17 of the motor 16 extends in a manner to longitudinally pass the inside of the blast duct 12. The rotary shaft passes through the center of the small diametered part 14 to protrude from an opening 15, while a heating bowl 18 formed in the shape of an inverted bowl is attached thereto. A funnel body 19, the diameter thereof increases as it approaches upward toward the upper end thereof, is mounted to the upper end of the rotary shaft 17 and in a position equivalent to that of the bottom of said bowl 18. The apex of a kerosine feeder 20 is open facing and opposite to the funnel body 19.