The present invention provides anti-mortalin peptide antibodies having stronger anticancer effects than known anti-mortalin antibodies, hybridomas producing such antibodies, and anticancer agents using such antibodies. Specifically, a hybridoma C-26 strain (FERM P-21875) and a hybridoma C-69 strain (FERM P-21876) producing anti-mortalin monoclonal antibodies having the function of being internalized by cancer cells and specificity to mortalin antigens, and having the good function of suppressing the cancer cell proliferation in vivo were obtained from hybridoma clones obtained using as an immunogen cocktail of the 2 types of peptide containing "LFGRAP" and "KAMQDAEVSKSDIGEVI" epitopes for an anti-mortalin antibody having the function of being internalized by cancer cells. Thus, anticancer agents containing the monoclonal antibodies as active ingredients could also be provided. Moreover, the epitope sequences recognized by these monoclonal antibodies were confirmed to be "EVILVG" and "DLFGR."
