The present invention relates to a combined fuel cell and boiler system, and comprising: a fuel cell portion for receiving supplied outside air and raw material gas and generating electricity through a catalyst reaction; and a boiler portion comprising a latent heat exchanger, which is connected to an exhaust gas pipe of the fuel cell portion, for collecting the latent heat of self-generated exhaust gas with the latent heat of exhaust gas from the fuel cell portion. The present invention can effectively increase the efficiency of a boiler by supplying the exhaust gas from the fuel cell to the latent heat exchanger in the boiler, so as to be heat-exchanged in the latent heat exchanger with the exhaust gas from the boiler and then discharged, and can simplify the composition by unifying exhaust gas pipes.