The present invention relates to a method for activating helper T cells, which includes the step of activating helper T cells by adding a WT1 peptide to antigen presenting cells, wherein the WT1 peptide has the ability to bind to an MHC class II molecule selected from HLA-DRB1*08:02 molecule, an HLA-DRB1*13:02 molecule, an HLA-DRB1*14:03 molecule, an HLA-DRB1*14:05 molecule, an HLA-DQB1*03:02 molecule, and an HLA-DQB1*04:01 molecule.