Abstract: A heat treatment boat for mounting a number of disc-shaped objects to be treated at a vertical interval for heat treatment thereof in a vertical heat treatment furnace comprises arcuate or ring-shaped support members provided on support rods at a vertical interval for supporting the objects to be treated in surface contact with the undersides of peripheral parts of the objects to be treated. The heat treatment boat is disposed on a ring-shaped intermediate member of high radiant heat absorption disposed on a heat insulating cylinder. The heat treatment boat comprises support rods which are planted on an annular support member circumferentially in accordance with a contour of the objects to be treated and whose upper ends are secured to an annular fixation member. The heat treatment boat of such constitution can reduce occurrences of slips in the disc-shaped objects when heat treated.