Abstract: A self-contained portable cryogenic apparatus that operates at the temperature (of the order of -78.degree. C. at atmospheric pressure) reached by reducing the pressure of carbon dioxide (CO.sub.2) or equivalent in liquid/solid phase, comprising a reservoir of pressurized liquefied CO.sub.2, the drawing off head being connected to a liquid/solid CO.sub.2 pressure reduction and ejection system, and comprising a control device, a pressure reduction device and a device for checking the temperature in the area to which it is applied, remarkable in that the top of the CO.sub.2 reservoir is arranged on the apparatus such that during the entire usage period, only the liquid part of the CO.sub.2 inside the reservoir comes into contact with the head so that it is drawn off and forced towards the application area through a pressure reduction and ejection system. The apparatus is particularly suitable for use in sports medicine in the form of a spray gun.