To provide a method and apparatus for parting a glass rod without causing a crack or rupture at a grasped root portion of the glass rod in parting the glass rod for producing a glass preform.The apparatus for parting the glass rod in a predetermined length by grasping both ends of the glass rod 11 is characterized by comprising a supporting unit 18 of Y-character shape for supporting an intermediate position between both ends of the glass rod 11 from the lower part, the supporting unit 18 having a carbon sleeve composed of a cylindrical body that is rotatable around each of two leg portions making up a forked leg portion as an axis, the carbon sleeve being rotatable along with an axial movement of the glass rod.