An appliance for relieving tachypnea of an infant belongs to the technical field of medical devices. When treated in a hospital, the infant possibly has tachypnea syndrome due to pain caused by the fear and the illness state of the infant, a medical worker often slightly covers an oral area of the infant with a hand to adjust the amount of inhaled carbon dioxide gas in order to eliminate the syndrome, the infant is possibly more frightened by the operation process, and the hand of the medical worker is contaminated. The technical scheme of the appliance includes that a lower end opening of a flare tube (1) is communicated with a silicon rubber gasket (6) in a fixedly connected manner, an upper end opening of the flare tube (1) is communicated with a thin straight tube (2) in a fixedly connected manner, a small-diameter end opening (4) is arranged at an upper end opening of the thin straight tube (2), a large-diameter end opening (5) is arranged at a lower end opening of the silicon rubber gasket (6), and a damper switch (3) is mounted on the thin straight tube (2). The appliance has the advantages that the appliance is simple and convenient in operation, time and labor are saved, and medical efficiency is greatly improved.