The present invention provides a compound expressed by formula (1) or a salt, etc., thereof. In formula (1): Xa and Ya represent single bonds, etc.； a cancer antigen peptide (A) represents an MHC class I-restrictive WT1 peptide comprising a 7-30 residue amino acid； R1 represents a hydrogen atom, a group expressed by formula (2) (in the formula, Xb and Yb represent single bonds, etc., and a cancer antigen peptide (B) represents an MHC class I-restrictive WT1 peptide comprising a 7-30 residue amino acid and having a different sequence to that of the cancer antigen peptide (A)), or a cancer antigen peptide (C)； and a cancer antigen peptide (C) represents an MHC class I-restrictive WT1 peptide or an MHC class II-restrictive WT1 peptide that comprise a 7-30 residue amino acid which contains one cysteine residue, and have a different sequence to that of the cancer antigen peptide (A)
