The present disclosure provides a method for manufacturing an excellent denatured whey protein having no adverse effect on the characteristics of a product. A method for manufacturing a denatured whey protein comprising processing a whey protein solution by repeating the following steps (1) and (2) 2 times or more continuously: (1) a step for treating the whey protein solution on pressure at 50 MPa or higher and on heating at 85 to 100°C and, (2) a step for decompressing to 0.05 to 0.5 MPa after the treating of the aforementioned step (1) and maintaining the temperature within the range of the heating temperature of the aforementioned step (1) ±10°C.