To obtain a deproteinized natural rubber latex sponge having dense texture and high quality and free from the danger of contact allergy with protein by hydrolyzing proteins contained in a natural rubber latex to form amino acids and subjecting the natural rubber latex to expansion molding.

Proteins contained in a natural rubber latex are hydrolyzed into amino acids e.g. by using preferably 0.001-0.1 pts.wt. (based on 100 pts.wt. of the solid component of the natural rubber latex) of a proteolytic enzyme such as alkaline protease and the obtained natural rubber latex is subjected to expansion molding to obtain the objective deproteinized natural rubber latex sponge.