PROBLEM TO BE SOLVED : To provide an anti-Helicobacter heilmannii agent which has an intragastric microorganism number-reducing action or eradication action against Helicobacter heilmannii which is clear to be involved in the development of gastritis, gastric ulcer, mucosa-associated lymphoid tissue (MALT) and the like, in intragastric infection to humans, dogs, cats, pigs, monkeys, and the like.SOLUTION : The invention provides an anti-Helicobacter heilmannii agent which contains as an active ingredient lactic acid bacteria and/or lactic acid bacteria culture belonging to Lactobacillus.SELECTED DRAWING : Figure 2