PURPOSE: To provide an automatic substrate processing/drying apparatus in which dust removal efficiency is improved and occurrence of inconvenient troubles due to sucked dust is avoided by arranging filters on the upstream side and downstream side of a gas guide passage on both sides of heating means.

CONSTITUTION: A drying chamber 21 includes a drying chamber body 32 in which there are formed openings 32a, 32b for carrying in and carrying out a cassette K in which a glass substrate is contained, shutters 33a, 33b for opening/closing the openings 32a, 32b, and driving means for actuating the shutters 33a, 33b. The cassette K is carried in and out of the drying chamber 21 through a belt conveyor and the like. A duct 36 is connected with the upper part of the drying chamber 21, and hot air fed through a heater 43 is blown off against the cassette K from the upper part. Further, a duct 45 is connected with the lower part of the drying chamber 21, through which duct 45 exhaustion is executed. A coarse filter 42 is provided on the upstream side of the heater 43 and a precision filter 44 is provided on the downstream side of the same.