An airtight container including a container body having an opening formed on an upper portion thereof, a lid for opening or closing the opening of the container body, and a rotating knob hingedly-connected to the container body, the airtight container comprising: the container body including a latching bump formed along an upper inner wall surface of an inner wall of the container body and a flange extending outwardly from an upper portion of the inner wall and then bent downward thereby forming a groove therein; the rotating knob connected to the flange and having an opening-closing plate and a step portion, and being vertically rotatable; and the lid including a latching protrusion formed along on an inner wall surface of an inner wall, a downwardly bent flange extending outwardly from a circumference of the inner wall and capable of being coupled downwardly to the flange, and a lid extension portion formed at the flange, wherein the lid extension portion is in contact with the opening-closing plate and the step portion in a state where the lid is coupled to the container body, or when the rotating knob is rotated upward in the state where the lid is coupled to the container body, wherein, when the rotating knob is just rotated upward in the state where the lid is coupled to the container body, the opening-closing plate lifts the lid extension portion by the principle of the lever and the step portion prevents the lid extension portion contacted with the step portion from spreading outwards, thereby allowing the latching protrusion to be released from the latching bump and the lid to be opened from the container body, wherein the rotating knob is rotatably connected to the flange through a film hinge, wherein the latching protrusion is formed by a closed loop-shaped packing member made of a soft resin and including a protrusion portion protruding from the inner wall surface of the lid towards the latching bump, and the packing member is fixed to the inner wall surface of the lid made of a material different from the packing member by a double injection so that the protrusion portion can be latched directly below the latching bump and wherein the soft resin is silicone. the container body including a latching bump formed along an upper inner wall surface of an inner wall of the container body and a flange extending outwardly from an upper portion of the inner wall and then bent downward thereby forming a groove therein; the rotating knob connected to the flange and having an opening-closing plate and a step portion, and being vertically rotatable; and the lid including a latching protrusion formed along on an inner wall surface of an inner wall, a downwardly bent flange extending outwardly from a circumference of the inner wall and capable of being coupled downwardly to the flange, and a lid extension portion formed at the flange, wherein the lid extension portion is in contact with the opening-closing plate and the step portion in a state where the lid is coupled to the container body, or when the rotating knob is rotated upward in the state where the lid is coupled to the container body, wherein, when the rotating knob is just rotated upward in the state where the lid is coupled to the container body, the opening-closing plate lifts the lid extension portion by the principle of the lever and the step portion prevents the lid extension portion contacted with the step portion from spreading outwards, thereby allowing the latching protrusion to be released from the latching bump and the lid to be opened from the container body, wherein the rotating knob is rotatably connected to the flange through a film hinge, wherein the latching protrusion is formed by a closed loop-shaped packing member made of a soft resin and including a protrusion portion protruding from the inner wall surface of the lid towards the latching bump, and the packing member is fixed to the inner wall surface of the lid made of a material different from the packing member by a double injection so that the protrusion portion can be latched directly below the latching bump and wherein the soft resin is silicone.