The utility model relates to a built-in carbon dioxide generator which is matched with a sealed type bactericidal-culture integrated culture medium by inside spins. Quantitative dry ice is quickly gasified under a room temperature condition, so that carbon dioxide gas is generated and stored in a sealed gasbag (4) of the generator. When the carbon dioxide generator is connected with the culture medium, a spring (2) is contracted and a supporting plate (5) ascends with screwing up of screws (1), and a hollow needle (3) pierces through the gasbag, so that the quantitative carbon dioxide is quickly released and stored in the culture medium. The built-in carbon dioxide generator disclosed by the utility model can replace a carbon dioxide incubator to lower equipment cost; the carbon dioxide is not leaked outsides, so that air in a laboratory is not polluted; aerosol does not spread into the incubator or a surrounding environment, so that the built-in carbon dioxide generator is safe and environmental friendly; the built-in carbon dioxide generator is convenient to operate, so that training is not needed; the built-in carbon dioxide generator is low in cost, and suitable for being popularized in various microorganism laboratories.