To provide a small-sized and highly efficient CO2 recovery type cogeneration system allowing CO2-free cogeneration while separately recovering it without discharging CO2 in an exhaust gas into the atmosphere.

A stratified air-fuel mixture consisting of pure oxygen or a mixture of the pure oxygen with a fuel at the center within a cylinder, and a circulating EGR gas on an outer peripheral part of the cylinder is burned to generate the exhaust gas consisting of only CO2 and steam, and CO2 is recovered at a high concentration by removing the steam while recovering heat by a heat exchanger. Downsizing and efficiency improvement of a device are promoted by directly using engine power in compression of the recovered CO2.