PURPOSE:To prevent abrasive whitening due to abrasion between blow bottles or the bottle and the inner wall of a box during the transport of the bottle, etc., and to increase the strength of the bottle simultaneously by heating the outer surface of the blow bottle at a high temperature. CONSTITUTION:The inside of a polyvinyl chloride group oriented blow bottle is filled with a liquid material, and the outer surface of said blow bottle is heated at a high temperature. The temperature of the surface of the bottle must be elevated to a high temperature in order to solve the molecular orientation of the surface of the bottle, and frame treatment through which a flame is brought into contact directly with a surface to be heated is preferable as a heating method for the surface. The time for a contact with the flame extends over treating time preferable according to the compounding of PVC, the size of the bottle, a flame temperature, etc., and is determined experimentally. When a 1 litre bottle and a propane flame (1,000 deg.C) are used, the bottle may be treated for 0.8-25sec while being turned. The liquid material filled into the bottle prior to heating prevents reaching to a high temperature of the inner layer section of the bottle through heating, and water, etc. are preferable. Accordingly, only the surface is treated at the high temperature in a short time in the oriented blow bottle, and abrasion resistance is obtained in the structure of a surface layer section.