PURPOSE: To obtain the fermented milk having good odor and keeping the quality by emulsifying an oil and fat containing readily oxidizable ω 3-based polyvalent unsaturated fatty acid into an oil-in water type emulsion and adding the emulsion to a fermented milk product fermented by lactobacillus, etc.

CONSTITUTION: An emulsifier is added to an oil and fat containing ω 3-based polyvalent unsaturated fatty acid (eicosapentaenoic acid, docosahexaenoic acid or α-linolenic acid) to emulsify the oil and fat into an oil-in water type emulsion. The emulsion is added to a milk product fermented by lactobacillus bacterium or yeast to provide a fermented milk having 0.001-1wt.% of ω 3-based polyvalent unsaturated fatty acid content. The fermented milk capable of moreover keeping for a long period is obtained by adding an antioxidant to a raw material oil and fat before emulsifying.