This invention provides a mucosal vaccine for transnasal or oral administration, which is capable of inducing vaccine antigen-specific immune responses in an organism without the addition of mucosal adjuvant. Such mucosal vaccine used for prevention or treatment of microbial infections comprises a composite of a nanogel comprising a hydrophilic polysaccharide having a cationic functional group and hydrophibic cholesterol added thereto as a side chain and a vaccine antigen, and it is administered via a mucosal route.