The present invention relates to a method for increasing the stemness of human mesenchymal stem cells and, more particularly, to: a method for increasing the stemness of human mesenchymal stem cells by means of endothelin-1 treatment; the human mesenchymal stem cells having increased stemness by using the method; and a composition for increasing the stemness of human mesenchymal stem cells, containing endothelin-1 as an active ingredient. In the present invention, it is confirmed that the expression of a stemness marker is increased and that a stem cell characteristic is improved such as the length of telomeres being extended, by treating human mesenchymal stem cells with endothelin-1, and thus cellular life span is extended, aging is inhibited, and the growth and viability of cells are increased, thereby enabling mass culturing of human mesenchymal stem cells such that human mesenchymal stem cells are expected to be used effectively in cell therapy or regenerative medicine.