In a processing apparatus according to one embodiment, a stage is installed inside a process chamber. The stage has a plurality of through-holes formed therein, which corresponds to a plurality of lift pins. The plurality of lift pins is supported by a spline shaft through a support body. The spline shaft is supported by a spline bearing such that the spline shaft is vertically moved. The plurality of lift pins is biased upward by a spring member through the spline shaft. The spline shaft, the spline bearing, and the spring member are installed in an outer space separated from a depressurizable inner space of the process chamber.