A powder inhalator including: a housing, a supply member for holding a powdered drug for a large number of doses and having a drug discharge aperture at its bottom surface; a drug carrier, to which the powdered drug is supplied from the drug discharge aperture of the supply member, and having on its upper surface a measuring recess that has a volume equivalent to one dose of the drug; and an operation member disposed so as to move freely back and forth, and operate the drug carrier; the drug carrier moving in contact with the bottom surface of the supply member to carry the powdered drug loaded into the measuring recess from the position of the drug discharge aperture to an air inhalation channel, wherein the drug carrier is disposed slidably so that the measuring recess moves in a circular manner by sliding the drug carrier.