The present invention relates to a pipeline controlling buoyancy. The pipeline controlling buoyancy is easily installed and maintained as it is installed around the surface of the sea. A part of the pipeline can be sunken down under the surface of the sea as necessary. The pipeline controlling buoyancy includes a plurality of pipes; a coupling member which connects the pipe in series by being installed between the pipes and connects the pipes to be bent; and a buoyancy controller controlling the buoyancy by being connected to at least one among the pipe or the coupling member.
