Assembly device and assembly method for semiconductor manufacturing device

An object of the invention is to provide technology that can reduce the duration of the assembly period for a semiconductor manufacturing device. An assembly device for semiconductor manufacturing devices according to one aspect of the present invention is a device for assembling semiconductor manufacturing devices that have a reaction tube with an opening at the bottom end, the assembly device comprising a main body, an elevator mechanism mounted to the main body that holds and can raise and lower the reaction tube, a gas supply mechanism that supplies a gas to the interior of the reaction tube, and an exhaust mechanism that exhausts the interior of the reaction tube.