A vertical type heat processing apparatus prevents falling-down of a boat placed on a heat insulating mount due to an external force, such as an earthquake. The apparatus includes a heating furnace having a furnace port, a cover, a pair of substrate holding tools, each to be placed on the cover via a heat insulating mount and to hold multiple substrates, a rotating mechanism, and a lifting mechanism to raise and lower the cover to carry in and carry out the substrate holding tool relative to the furnace. While one of the substrate holding tools is located in the furnace, the other is placed on a table, for loading the substrates. Each substrate holding tool is carried between the table and the heat insulating mount due to a carrier mechanism. Further, a locking part and a part to be locked can be engaged with each other.