With an object of discovering a substance having a testosterone 5.alpha.-reductase inhibiting action, a hair papilla cell growth promoting action, a fibroblast growth factor-7 production promoting action, a vascular endothelial growth factor production promoting action or a bone morphogenetic protein-2 production promoting action, and of providing a hair care product having this substance blended therein, and a hair growth tonic, a testosterone 5.alpha.-reductase inhibitor, a hair papilla cell growth promoter, a fibroblast growth factor-7 production promoter, a vascular endothelial growth factor production promoter and a bone morphogenetic protein-2 production promoter each having this substance as an active ingredient thereof, a hair care product of the present invention is made to contain corosolic acid therein, and each of a hair growth tonic, a testosterone 5.alpha.-reductase inhibitor, a hair papilla cell growth promoter, a fibroblast growth factor-7 production promoter, a vascular endothelial growth factor production promoter and a bone morphogenetic protein-2 production promoter of the present invention is made to contain corosolic acid as an active ingredient thereof.