PROBLEM TO BE SOLVED : To provide an unconventionally new composition for promoting increase of Akkermansia muciniphila, and a food, pharmaceutical, and feed containing the composition. SOLUTION : The present invention provides a composition for promoting increase of Akkermansia muciniphila, containing κ-casein glycomacropeptide (GMP) as an active ingredient. There are also provided a food and drink, pharmaceutical, and feed for promoting increase of Akkermansia muciniphila, containing GMP as an active ingredient. SELECTED DRAWING : Figure 2 COPYRIGHT : (C)2019, JPO&INPIT