The inventors of this invention have conducted the search for a variety of compounds which may possess a desired CaSR agonist activity to thus find out a substance capable of imparting a kokumi, which shows a more excellent kokumi-imparting effect, in particular, a kokumi-imparting effect of the initial taste-imparting type one, which is excellent in the stability and which can easily be produced at a low cost and the present invention thus provide a kokumi-imparting agent consisting of such a substance as well as a complex kokumi-imparting agent comprising the substance and other substances possessing the CaSR agonist activities in combination. More particularly, the present invention herein provides a kokumi-imparting agent consisting of γ -Glu-Abu (L- γ -glutamyl-L-2-amino- butyric acid) and a complex kokumi-imparting agent comprising the foregoing substance and another substance having a CaSR agonist activity, in combination.