An object of the present invention is to provide a deterioration-odor masking agent and a deterioration-odor masking method capable of effectively masking deterioration odor of dairy products.The object is attained by a masking agent comprising one or more members selected from the group consisting of menthyl acetate, linalyl acetate, isoamyl isovalerate, isoamyl butyrate, nerol, acetaldehyde, methyl salicylate, 1,8-cineole, maltol isobutyrate, ethyl pyruvate, heliotropine, diethyl malonate, γ-butyrolactone, ethyl levulinate, benzyl alcohol, hexanal, γ-hexalactone, ethyl propionate, and amyl acetate.
