Substrate heat-treating furnace

Patent Granted The invention relates to a substrate treating furnace which can efficiently discompose organic matter contained in discharged hot wind by heating treatment. A glass substrate (W) is subject to heating treatment by blowing hot wind into the internal of a main body (10) of the furnace. The hot wind discharged from the main body (10) of the furnace returns to the main body (10) of the furnace again through a circulating path (20). Part of the hot wind is discharged to an exhaust pipe (23) in the midway of the circulating path.