Provided is an emulsified composition for diluting a cancer antigen peptide or a dimer thereof. Also provided is a novel cancer vaccine composition or specific CTL inducer that efficiently induces CTL irrespective of the type of cancer antigen peptide when mixing the emulsified composition for dilution and a water phase comprising a cancer antigen peptide or a dimer thereof.The present invention relates to an emulsified composition for diluting a cancer antigen peptide or a dimer thereof, comprising a particular ester, a particular surfactant, a particular emulsifier, and a water phase. The present invention also relates to a cancer vaccine composition or specific CTL inducer obtained by freshly diluting and mixing a water phase comprising a cancer antigen peptide or a dimer thereof with the emulsified composition for dilution.