According to the present invention, an apparatus for injecting gas into a floating container assembles an injection seal with a wing sealed on an injection line and an injection port to inject gas on an injection port of a container, injects gas into the container, and comprises: an aligning waiting plate forming a seating groove to align and arrange the container to allow a plurality of containers to be aligned and wait； a horizontal support plate having a plurality of guide holes penetrated to allow the container aligned and arranged on the aligning waiting plate to pass； a fixing unit having a plurality of vertical fixing parts which are vertically installed on the horizontal support plate and have a stopping groove to hold a container fixing part with a plurality mounting holes penetrated to allow containers to be inserted and mounted thereon, and a horizontal operating part operated forwards and backwards to come in contact with the container fixing part held on the stopping groove of the vertical fixing parts or be separated from the container fixing part to fix a position of the container fixing part or release the container fixing part； an external operating body having a coupling protrusion elastically coupled to the injection port of the container on a lower end thereof corresponding to the injection port of the container to be lowered through the mounting holes and the guide holes and be lifted through the mounting holes and the guide holes to insert and arrange the container coupled to the coupling protrusion into the mounting holes； and an internal operating body which is lowered to allow an injection seal coupled to a lower end thereof corresponding to the injection port of the container to be inserted into the injection port of the container, is connected to a gas supply line to which gas is supplied to inject gas into the container, and then is lifted to be separated from the injection seal.COPYRIGHT KIPO 2017본 발명은 기체를 주입하는 주입라인과 주입구에 밀봉되는 날개를 갖는 주입밀
