Disclosed is a flavor-enriching agent comprising a substance discovered by searching for a number of variation compounds having a CaSR-agonizing activity. Said substance exhibits a potent flavor-enriching action, particularly with respect to middle tastes, and exhibits an improved stability. Also disclosed is a composite flavor-enriching agent comprising said substance and another substance having a CaSR-agonizing activity. Specifically disclosed are a flavor-enriching agent comprising γ-Glu-Nva-Gly (L-γ-glutamyl-L-norvaline-glycine), and a composite flavor-enriching agent comprising said substance together with another substance having a CaSR-agonizing activity.
