Cogeneration System

The invention provides a cogeneration system capable of adjusting a heat-to-electric power ratio not only in an increasing direction, but also in a decreasing direction. The cogeneration system includes: a power generation device configured to supply electric power; a first heat exchanger configured to exchange heat between exhaust of the power generation device and water, so as to lower a temperature of the exhaust and obtain steam from the water; a reformer configured to generate a reformed gas by the steam reacting with a fuel; a second heat exchanger configured to cool the reformed gas generated by the reformer by heat exchanging; a reformed gas supply device configured to supply the reformed gas cooled by the second heat exchanger to the power generation device; a distributor configured to supply the steam to at least one of the reformer and a heat utilization device; and a control device configure to adjust a heat-to-electric power ratio by changing a supply destination of the steam in the distributor.