To provide an in-line type vacuum heat treatment furnace in which an inside section of it is hardly contaminated by wax and a sintered product having a high quality can be supplied in a stable manner for a long period of time.

A wax removing chamber 2 is constructed by a transporting space 21 into which a treated item S is transported and a wax removing space 23 below the transporting space 21. A closing lid 33 for the wax removing space 23 is fixed to the lower end of an ascending or descending rod 32 inserted from the ceiling surface of the transporting space 21 and then there are provided supporting columns 34 suspended from the lower surface of the closing lid 33 to support a treated item S. As the treatcd item S is transported into the transporting space 21, the ascending or descending rod 32 is lowered to sealingly enclose the treated item S in the wax removing space 23, then it is heated by an electrical heater 36, air is removed or discharged by a vacuum pump 26 so as to remove wax.