A novel micro cell incubator is described in this paper. pH of animal cell culture media must be tightly controlled, and this is accomplished by supplying defined concentration of carbon dioxide. In order to fabricate a small self-contained carbon dioxide supply unit, we adopted chemical production of carbon dioxide rather than compressed storage of the gas which requires huge tank. Carbon dioxide can be chemically produced by pyrolysis of sodium bicarbonate. The produced gas passes through a thin polymer membrane which is known to admit diffusion of gases. Liquid media separated from gas area by polymer membrane can uptake the gas, then. This micro cell incubator would be a suitable model for the development of portable and arrayed cell chips.