To provide a batch type heat treatment furnace which saves energy of a heat source, and has high space efficiency, high conveying efficiency of treatment objects, low facility costs, and small heat loss.

The batch type heat treatment furnace 1 includes: a carriage 3 having a mounting part 30 having a low temperature part 300f mounted with a low temperature treatment object Wf and a high temperature part 300r mounted with a high temperature treatment object Wr, and a partition part 31 partitioning the low temperature part 300f and the high temperature part 300r and erected on the mounting part 30; and a housing 5 having a heat treatment chamber 500 which allows entry and exit of the carriage 3 and which is divided by the partition part 31 into a low temperature chamber 500f subjecting heat treatment to the low temperature treatment object Wf, and a high temperature chamber 500r subjecting heat treatment to the high temperature treatment object Wr by housing the carriage 3 in the heat treatment chamber 500. At least one parts of a heat source of the low temperature chamber 500f and a heat source of the high temperature chamber 500r are shared by circulating gas used as a heating medium.