The present invention provides a manufacturing method of a hydrolysate of animal protein, comprising: primarily removing fat from a source of the animal protein; and hydrolyzing a resultant product with a protease under a high pressure. In the case of manufacturing a hydrolysate of animal protein by the manufacturing method according to the present invention, a degree of hydrolysis is very high, and since rancidification or growth of microorganisms is suppressed during the manufacturing process, reliability of product quality and energy cost are excellent in economic terms. Further, in a hydrolysate of animal protein according to the present invention, most of the hydrolyzed protein is degraded into 1 kDa or less, and, thus, it is excellent in rate of absorption from the small intestine.