The purpose of the present invention is to provide a mucosal vaccine composition that is effective and safe as a prophylactic or therapeutic drug for infections and cancer, which effectively induces a systemic immune response and mucosal immune response, and which can be administered to the oral mucosa, ocular mucosa, ear mucosa, genital mucosa, pharyngeal mucosa, respiratory mucosa, bronchial mucosa, pulmonary mucosa, gastric mucosa, intestinal mucosa, or rectal mucosa. The present invention is a mucosal vaccine composition administered to at least one mucous membrane of a person or animal, said mucous membrane being selected from the group consisting of oral mucosa, ocular mucosa, ear mucosa, genital mucosa, pharyngeal mucosa, respiratory mucosa, bronchial mucosa, pulmonary mucosa, gastric mucosa, intestinal mucosa, and rectal mucosa. The mucosal vaccine composition is characterized by including at least one type of antigen, and, as an immunostimulant, a lipopolysaccharide or a salt thereof 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.
