To provide a method for manufacturing a hollow metal component capable of obtaining a hollow metal member, light weight and excellent in dimensional accuracy in the relatively small number of processes.

The method for manufacturing the hollow metal component comprises the step of preparing a pair of upper and lower metal split pieces 10, 20 which can constitute the outer shell of a turbine housing (one type of the hollow metal component) by combining with each other. The method further comprises the steps of combining the pieces 10, 20, and welding the connecting sites C to form a preformed product having a hollow part therein. The method also comprises the steps of applying a hydraulic pressure to the interior of the preformed product in the state in which the preformed product is housed in an additional dies (41 to 44) to impart the profile shape corresponding to the internal shape of the additional die to the preformed product.