The present invention is represented by the formula (1): [wherein Xa and Ya represent a single bond and the like, cancer antigen peptide A represents an MHC class I-restricted WT1 peptide consisting of 7 to 30 amino acids, and R1 represents Hydrogen atom, formula (2): (wherein Xb and Yb represent a single bond, etc., and cancer antigen peptide B has a sequence different from that of cancer antigen peptide A and is composed of 7 to 30 amino acids. Represents a constrained WT1 peptide.) Or a cancer antigen peptide C. The cancer antigen peptide C has a sequence different from that of the cancer antigen peptide A and includes 7 to 30 residues including one cysteine residue. An MHC class I-restricted WT1 peptide or MHC class II-restricted WT1 peptide consisting of the following amino acids: Or a salt thereof, and the like.本発明は、式(1):[式中、XaおよびYaは単結合などを表し、癌抗原ペプチドAは7~30残基のアミノ酸からなるMHCクラスI拘束性WT1ペプチドを表し、R1は、水素原子、式(2):(式中、XbおよびYbは単結合などを表し、癌抗原ペプチドBは、癌抗原ペプチドAとは配列が異なり且つ7~30残基のアミノ酸からなるMHCクラスI拘束性WT1ペプチドを表す。)で表される基、または癌抗原ペプチドCを表し、癌抗原ペプチドCは、癌抗原ペプチドAとは配列が異なり且つ1つのシステイン残基を含む7~30残基のアミノ酸からなるMHCクラスI拘束性WT1ペプチドまたはMHCクラスII拘束性WT1ペプチドを表す。]で表される化合物またはその塩などを提供する。