PURPOSE: To provide the titled drying chamber having good heat efficiency due to good seal effect and capable of holding good seal effect for a long period constituted so as to make it possible to move a drying chamber to forward and backward directions against a cover and drying to contact said drying chamber with the cover under pressure during to hermetically seal a connecting part.

CONSTITUTION: The drying chamber 10 is provided in such a condition that it can be moved to forward and backward directions as shown by an arrow against a screen 1 or the like by an air cylinder 28 and, during drying, contacted with the cover 11 under pressure. A hot air duct 15 has a leading duct part 15a connected to said drying chamber by a bellow 29. To a periphery of an end surface of the drying chamber 10, a seal packing 30 formed by usig a heat resistant elastomer material is provided.