The present invention relates to a composition for immunostimulation useful for promoting IgA and secretory component productions in mucosal tissues, comprising, alone or in combination, a cell of bifidobacterium belonging to Bifidobacterium bifidum or a processed product thereof, wherein the bifidobacterium has an activity to stimulate secretory component production and a high activity to stimulate IgA production, for example, it is a Bifidobacterium bifidum OLB 6377 strain or Bifidobacterium bifidum OLB 6378 strain.
