PURPOSE: To provide a continuous type heat treatment furnace and a housing container for material to be treated which achieves a reduction in cost with restricted feeding of an atmospheric gas by enabling the controlling of the concentration of the atmospheric gas precisely.

CONSTITUTION: A roller hearth furnace 1 is provided with a furnace body 2, an electric heater 4 to heat a ceramic product 3 and a plurality of hearth rollers 6 which are arranged in parallel with one another while transporting a housing container 5 for material to be treated housing the ceramic product 3. Both ends of the hearth rollers 6 are connected to an atmospheric gas supply source through a tube 10 while an atmospheric gas jetting port 12 is provided on the circumferential surface of the hearth roller 6 to jet out an atmospheric gas supplied from the atmospheric gas supply source to an opening part 11 provided in the housing container 5 for the material to be treated. The housing container 5 for the material to be treated comprises a box for housing the ceramic product 3 and a lid member and a cut part is provided at a side wall part of the box to introduce the atmospheric gas into a housing space.