Abstract: Disclosed is a safety intravenous set in which a spherical ball is provided in a transparent barrel for confirming a flow of the Ringer's solution to easily float up due to its own buoyancy when the Ringer's solution is injected so that the Ringer's solution is facilely administered through a supplying tube, and also, when the administration of the Ringer's solution is completed, the spherical ball automatically blocks an outlet port so as to efficiently prevent a back flow of blood of the patient. The transparent barrier has a double-curbed structure at a lower portion thereof, and also has a hemispherical settling portion for easily floating up the spherical ball when the Ringer's solution is introduced into the transparent barrier.