An embodiment of the present invention relates to a method for manufacturing high-chromium (Cr) molten steel having a chromium (Cr) content of 4.5 wt % to 5.5 wt %, and the method may comprise the operations of: inserting molten steel into a steel converter used in the process of manufacturing stainless steel; and inputting chromium (Cr)-containing chromium steel alloy into the steel converter such that the content of chromium (Cr) in the molten steel reaches 4.5 wt % to 5.5 wt %. Therefore, according to the embodiments of the present invention, high-chromium (Cr) molten steel can be manufactured by using a steel converter that is used in the steelmaking process of other steel types, without contaminating same.