Cancer vaccine therapy is one of the new treatment modalities for gastric cancer at the advanced stage. In this study, we have identified HER2 peptide epitopes restricted by HLA-A24, which is one of the most common alleles in Japanese. We generated immature DCs from PBMCs in a HLA-A24+, HER2+ gastric cancer patient. Immature DCs were co-incubated with irradiated PC-9 cell line, and then autologous PBMCs were co-incubated with PC-9-derived antigen-loaded DCs. As a result, we were able to generate HER2 reactive, HLA-A24-restricted CTL lines. The CTL's specificity was evaluated with ELISPOT analysis and cytotoxic assay. The CTLs specifically recognized cancer cells expressing HLA-A24 and HER2. We synthesized a set of HLA-A24 binding, HER2-derived peptides to identify HLA-A24 restricted peptide epitopes derived from HER2. In conclusion, we were able to identified HER2 peptide epitopes restricted by HLA-A24, suggesting that these epitopes will be new targets for cancer vaccine therapy.