The purpose of the present invention is to provide a novel medicinal use in regeneration medicine, said medicinal use comprising using pluripotent stem cells (Muse cells). Provided is a cell preparation for treating skin ulcer, said cell preparation comprising SSEA-3 positive pluripotent stem cells isolated from a mesenchymal tissue of a living organism or cultured mesenchymal cells. The cell preparation according to the present invention is based on such mechanism of skin tissue regeneration that, when the Muse cells are administered to a skin ulcer site of a subject suffering from the aforesaid disease, the Muse cells differentiate into skin-constituting cells.
