The present invention addresses the problem of providing a low-molecular weight adjuvant which can be administered safely without inducing skin irritation or the like by transdermal or transmucosal administration and is for efficiently enhancing the immunogenicity of an antigen. The present invention relates to an adjuvant for transdermal or transmucosal administration, containing at least one member selected from polyhydric alcohols and derivatives thereof including glycerol, glycerol derivatives and the like.
