Provided is a method for activating a good intestinal bacterium for the purpose of improving an intestinal bacterial flora. A method for activating a good intestinal bacterium, comprising selecting multiple oligosaccharides that are suitable for the activation of a good intestinal bacterium of interest, combining the multiple oligosaccharides at a content ratio suitable for the activation of the good intestinal bacterium, and administering the resultant combination to an intestinal bacterial flora. The method for activating a good intestinal bacterium can achieve an improving effect on an intestinal bacterial flora for which the environment is varied among individuals, physical conditions, ages and the like.
