Abstract: The present invention provides a method starting from cells derived from a mammalian endodermal tissue or organ (except for the liver) to produce stein/progenitor cells thereof, which comprises bringing the cells derived from the endodermal tissue or organ into contact in vitro with a TGF?-receptor inhibitor.

Abstract: The purpose of the present invention is to provide a micro-needle having a leading end that can reach the dermis with certainty by penetrating through the epidermis when piercing the skin and that can supply a drug or the like to the dermis or to a region deeper than the dermis. Accordingly, this micro-needle (10) has a base (1) and a plate-shaped blade (2). The plate-shaped blade (2) and the base (1) are formed in an integrated manner, and the plateshaped blade (2) extends from an end (1A: step section) of the base (1). Alternatively, the present invention is characterized by having a base (111) and a conical leading end part (112) and a star-like polygonal cross-sectional shape part (114, 124) being formed in a region between the base (111) and the conical leading end part (112), and in that the base (111), the conical leading end part (112) and the starlike polygonal cross-sectional shape part (114, 124) are formed in an integrated manner.