A method of manufacturing an integral type crankshaft bearing cap for an internal combustion engine. The integral type crankshaft bearing cap comprises crankshaft bearing caps spacedly arranged in the longitudinal direction of the engine and a beam extending in the longitudinal direction of the engine. The manufacturing method comprises making a plurality of models of the crankshaft bearing caps of resin used in full mold casting, arranging the models and connecting the models to the beam, and replacing the resin constituting the models with metal in full mold casting, thereby integrating the replaced metal and the beam.