A mucosal vaccine producing an antigen-specific mucosal IgA and a blood IgG in the levels capable of exerting an effective immune induction and an infection-preventing effect, which comprises: (a) an AD vehicle consisting of a synthetic peptide and a lipid(s), wherein the synthetic peptide consisting of the amino acid sequence KnLm (wherein n is 4 to 8 and m is 11 to 20); (b) a carboxyvinyl polymer; and, (c) an antigenic protein, in an amount incapable of producing a sufficient mucosal IgA and blood IgG for exerting an effective immune induction and an infection-preventing effect when used by itself. The mucosal vaccine of the invention has an antibody producing ability which is more potent than those of mucosal vaccines of the prior art, and as a result it can exert an excellent effect even with an extremely small amount of an antigen.