<;P>;PROBLEM TO BE SOLVED: To provide an intestinal immune power increasing agent by using a lactobacillus (vegetable lactobacillus) having intestinal immune power increasing action by the improvement of IgA antibody production in the intestines and useful as a nature-originated safe food raw material. <;P>;SOLUTION: The invention provides an intestinal immune power increasing agent containing a lactobacillus belonging to Lactobacillus plantarum having high IgA antibody production improving action and intestinal immune power increasing action, preferably Lactobacillus plantarum AYA strain deposited as a deposition number FERM P-21106, as an active component. <;P>;COPYRIGHT: (C)2008,JPO&INPIT