ProblemThe purpose of the present invention is to provide: a chiral nucleic acid adjuvant having immunity-inducing activity and an immunity-inducing activator.SolutionThe present invention relates to an adjuvant which comprises oligonucleotides which comprise two to four sequences each represented by 5′-X1CpG X2-3′ and has a length of 14 to 32 nucleotides, wherein a nucleic acid at 3′ end side of at least two CpG motifs is connected by phosphorothioate linkage, wherein each nucleic acids at 3′ end and 5′ end of the oligonucleotide is S type nucleic acids connected by phosphorothioate linkage, and wherein the oligonucleotide comprises at least one nucleic acid without phosphorothioate modification. The present invention relates to an immunity-inducible activator comprising the adjuvant.
