A cogeneration apparatus including a polymer electrolyte fuel cell that generates electric power using a fuel gas and oxidizing gas; an internal circulation circuit that circulates an internal heat transport medium into the fuel cell; internal circulating means of circulating the internal heat transport medium; first heat exchanging means of exchanging heat of the internal heat transport medium with an external heat transport medium; a fuel cell main unit that incorporates the fuel cell, the internal circulation circuit, the internal circulating means and the first heat exchanging means; and heat utilizing means of utilizing heat of the external heat transport medium heat-exchanged by the first heat exchanging means through waste heat collecting pipes.