The present invention provides a WT1-derived HLA-DRB1*0405-binding antigen peptide, a polynucleotide encoding said peptide, a helper T cell inducer comprising said peptide or polynucleotide, and the like. It is related to a partial peptide consisting of 10 - 25 contiguous amino acids in the amino acid sequence of human WT1 shown in SEQ ID NO: 1, which binds to HLA-DRB1*0405 and induces helper T cells, a polynucleotide encoding said peptide, or a helper T cell inducer comprising said peptide or polynucleotide.