Abstract: A cogeneration system (10a) of the present disclosure includes an internal combustion engine (21), a first power generator (22), a first coolant circuit (23), a first heat exchanger (24), a second coolant circuit (25), a Rankine cycle power generation apparatus (26), and an exhaust gas supply path (40). The Rankine cycle power generation apparatus (26) includes a pump (27), an evaporator (28), an expander (29), a second power generator (30), and a condenser (31). The evaporator (28) heats and evaporates a working fluid with exhaust gas from the internal combustion engine (21). The exhaust gas supply path (40) delivers the exhaust gas from the internal combustion engine (21) to the evaporator (28) without allowing the exhaust gas to exchange heat with a liquid. The condenser (31) has a flow path (31a) through which the first coolant flows and which forms a part of the first coolant circuit (23).