A stocker for holding a plurality of reticle pods is provided. Each of the reticle pods is configured to accommodate a reticle assembly. The reticle assembly includes a reticle and a pellicle covering the reticle. The stocker includes a main frame and an electrostatic generator. The main frame has an inner space and at least one pod support disposed in the inner space. The pod support divides the inner space into a plurality of chambers configured to respectively accommodate the plurality of reticle pods. The electrostatic generator is coupled to the reticle assembly and configured to generate static electricity to the reticle assembly. The static electricity alternates between positive electricity and negative electricity.