From fish egg skin produced by utilization of roe grains of various fish, constituent proteins thereof are enzymatically degraded to obtain peptides and amino acids, of which effective utilization is achieved. The invention provides a method for producing amino acids and peptides (useful as nutrient enhancers for foods) from fish egg skins which comprises treating cold water-washed fish egg skins with ozonized water at room temperature or below, subsequently, degrading the resultant product with a proteolytic enzyme produced by Bacillus subtilis, or further treating with a proteolytic enzyme produced by Aspergillus oryzae, to degrade myogenic fiber proteins (contractile proteins: myosins) in the fish egg skin, and then concentrating/drying the degraded solution.