A HORIZON TYPE OF COMPLEX BOILER

A horizontal composite boiler is provided to simplify the structure by combining a firewood boiler, a fuel boiler, and a heat-storage boiler and to improve economic property by using the most efficient fuel. A horizontal composite boiler(100) comprises a horizontal combustion chamber(110) formed with a fire hole(131) at one side to insert firewood to burn the supplied fuel so as to generate heat; a housing(140) surrounding the combustion chamber to form a closed space at the outer side of the combustion chamber; a flue(120) communicated with the combustion chamber and elongated through the housing to the outer side of the housing; a burner(190) disposed in the combustion chamber to burn the supplied fuel; at least one electric heater(198) combined with the housing to be elongated inward the housing; and plural couplers(151~157) combined with water service/discharge pipes and formed at the outer side of the housing to supply and discharge water to the inner side of the housing.