The invention relates to a storage device (61) disposed in a clean room for storing product containers (2) for receiving wafers used in the production of semiconductors. The inventive storage device (61) is connected to an in-house transport system for the product containers (2). In order to utilize so far non-utilized zones of the clean room for the purpose of storage, thereby reducing capital cost and overhead expenses of semiconductor production, the storage device (61) is disposed below the ceiling of the clean room.