PURPOSE: To carry out drying process in which the difference between a high temperature section and a low temperature is clear by installing reflection plates on both sides of a near infrared ray lamp set facing the inner section direction of the drying oven and also in the direction in which the irradiation density of near infrared rays to be emitted gets higher.

CONSTITUTION: A near infrared ray lamp 22 is set facing the inner section direction of a drying oven 11. Reflection plates 24 and the drying oven are installed on both sides of the near infrared ray lamp 22 and also in the direction in which the emission density of near infrared rays to be emitted gets higher. As a result, the drying process in which the difference between a high temperature section and a low temperature section is clear can be carried out to improve the efficiency.