The present invention provides an allergy vaccine composition that is useful as a prophylactic or therapeutic agent for an allergic disease and can safely and effectively induce immune tolerance. The vaccine composition is to be administered to a human or animal with an allergic disease for the prevention or treatment of the allergic disease. The vaccine composition contains: an immunomodulator which is a lipopolysaccharide derived from at least one gram-negative bacterium selected from the group consisting of Serratia, Leclercia, Rahnella, Acidicaldus, Acidiphilium, Acidisphaera, Acidocella, Acidomonas, Asaia, Belnapia, Craurococcus, Gluconacetobacter, Gluconobacter, Kozakia, Leahibacter, Muricoccus, Neoasaia, Oleomonas, Paracraurococcus, Rhodopila, Roseococcus, Rubritepida, Saccharibacter, Stella, Swaminathania, Teichococcus, Zavarzinia, Pseudomonas, Achromobacter, Bacillus, Methanoculleus, Methanosarcina, Clostridium, Micrococcus, Flavobacterium, Pantoea, Acetobacter, Zymomonas, Xanthomonas, and Enterobacter, or a salt of the lipopolysaccharide; and at least one allergen.