The objective of the present invention is to provide a nasal mucosal vaccine composition that is safe, useful as a prevention or treatment agent for cancer or infectious disease, and can effectively induce a systemic immune response and a mucosal immune response. The nasal mucosal vaccine composition, which is administered to the nasal mucosa of humans or animals, is characterized by containing at least one type of antigen (but excluding influenza virus-derived antigens) and, as an immune activation agent, a lipopolysaccharide derived from at least one gram-negative bacteria 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 thereof.
