To form a uniform shape by arranging a guide plate in the center of a recess of a part where a drum and glass tubes contact with each other so as to keep a regular interval in order to keep an interval between two tubes constant.

A central part of a straight sealed tube is heated and softened by a gas burner, and is faired in a U shape, and this is heated and softened further by a heating furnace, and a recess 4 of a sealing part is gripped, and is pulled and introduced to a winding drum 3. The winding drum 3 has a semicircular recess, and a guide plate 2 to keep an interval between glass tubes constant is also arranged in a central part. An almost annular double rung-shaped lamp can be formed by this fairing work. However, since an end part remains in a straight shape, this part is heated and softened further later on, and is faired in an annular shape. After this fairing is completed, noble gas and mercury are sealed after air is exhausted through an exhaust pipe 5. Therefore, the same effect such as two lamps are arranged on the same plane can be obtained, and high illuminance according to the realization of high watt can be attained.