PURPOSE: To prevent a batch type heat treatment apparatus, in which the heat treatment is executed to a treated material of wire rod, etc., wound in the coil state and descaling property is improved to easily detach the scale produced on the surface.

CONSTITUTION: The apparatus is composed of heating chambers 1a, 1b, 1c, in which the air is introduced to produce the thick scale on the surface of the treated material 6 after executing heating, soaking and the prescribed heat treatment to the treated material 6 by charging the treated material 6 of the wire rod, etc., in the chamber kept to reducing atmosphere, and a cooling chamber 13, in which the treated material 6 taken out from the heating chambers 1a, 1b, 1c is rapidly cooled with air blast.