Problem The purpose of the present invention is to provide: a chiral nucleic acid adjuvant having immunity-inducing activity and an immunity-inducing activator. Solution The present invention relates to an adjuvant which comprises oligonucleotides which comprise two to four sequences each represented by 5-X 1 CpG X 2 -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.
