A multitray culture system was devised for cell culture and interferon (IFN) production on a large scale. The system consisted of a cell culture apparatus which has stacked multitrays and a reservoir. All components of the system were made of nontoxic, nonmutagenic, washable, and autoclavable materials, so that the system can be repetitively used in suitable condition for cultivations of anchorage-dependent cells with low running cost. Large quantities of mouse IFN (containing both MuIFN-alpha and MuIFN-beta) from mouse L cells and human beta interferon (HuIFN-beta) from human fibroblast cells, respectively, were obtained very efficiently using this system in comparison with roller bottle, bulk culture vessel, and microcarrier systems.