PURPOSE: To dispose a necessary quantity of electrodes of a high-frequency induction heater in the steps of moving upward and downward a sheet, to large ly shorten a horizontal distance and to reduce in size a dryer by forming a dry cooling passage substantially in a loop state extended in a vertical direction.

CONSTITUTION: After one surface of a sheet 30a is starched, it is conveyed vertically in a looped state. A guide roller of this case is disposed inside the loop thereby to eliminate adherence of undried starch to the roller, and a horizontal distance of conveying the sheet can be shortened. In the case of the sheet 30a having an width of about 20 inches, it is so adjusted as to apply a tension of about 5-15kg in a conveying direction of the sheet 30a, and adhered starch is dried without generating a distortion at the sheet 30a of a feeding state. Further, flapping of the sheet at the time of feeding is prevented. A sheet passage length can be shortened by cooling it after drying, and the loop can be reduced.