Abstract: The present invention provides large, high-purity quartz glass plate with a high degree of smoothness and flatness, its manufacturing method and equipment. The invention is characterized by the procedure in which a quartz glass tube with an opening over a specific width, in the direction of the tube shaft, that is preferably band-shaped, is heated and softened in a band-shaped area over the entire width, in the direction of the tube shaft, progressing sequentially along the direction of tube circumference from a specific position on the glass tube. While softening and heating, the quartz glass tube is pulled in a line approximately tangential to the specific position to flatten the glass tube.