Disclosed is an apparatus of manufacturing a pipe-shaped insulator, wherein a thin fiberglass mat is coated, at a surface thereof, with a binder (adhesive) and is press-wound on a forming roller, so as to manufacture a pipe-shaped insulator having a predetermined thickness and a predetermined diameter. The apparatus includes a mat feeding roller, a plurality of fiberglass mat transportation rollers, a coating roller to coat a binder over a surface of the fiberglass mat, a forming roller on which the fiberglass mat, coated with the binder, is wound in plural times to form a pipe-shaped insulator, a squeeze roller disposed parallel to the forming roller, a pressure regulator to press the fiberglass mat, an encoder to measure a transported length of the fiberglass mat, a cutting unit to diagonally cut the fiberglass mat, a control system, a sensor, and a plurality of drive motors and power transmission members.