To solve problems of the generation of malodor and opaqueness by easy technique by preparing a material composed of the specific amount of a propylene-ethylene random copolymer having a specific content of ethylene and the specific amount of a rosin metal salt.

The amount of 0.03 to 2 pts.wt. of a rosin metal salt is blended with the amount of 100 pts.wt. of a propylene-ethylene random copolymer having 2 to 6wt.% of an ethylene content. The rosin in the rosin metal salt is prepared from natural rosin, or a modified rosin of evey kind which is obtained by modifying natural rosin, or a refined rosin obtained by refining those rosins, while lithium, sodium or potassium is particularly preferable as the metal. A rosin metal salt in which the rate of reaction of rosin with metal is 50% or less has a high effect in proportion to its blending amount. Further, a stretch blow molding method, particularly, an injection stretch/biaxial stretch blow molding method, in which stretch is particularly performed at a stretch ratio of 1.5 or more, is preferable as the stretch blow molding method.