The present invention provides a compound represented by the formula (1): wherein X a and Y a are each a single bond and the like, cancer antigen peptide A is an MHC class I-restricted WT1 peptide consisting of 7 - 30 amino acid residues, R 1 is a hydrogen atom, a group represented by the formula (2): wherein X b and Y b are each a single bond and the like, cancer antigen peptide B has a sequence different from that of the cancer antigen peptide A, and is an MHC class I-restricted WT1 peptide consisting of 7 - 30 amino acid residues, or cancer antigen peptide C, and cancer antigen peptide C has a sequence different from that of the cancer antigen peptide A, and is an MHC class I-restricted WT1 peptide or an MHC class II-restricted WT1 peptide, consisting of 7 - 30 amino acid residues containing one cysteine residue, or a salt thereof, and the like.