(B) Obtained by Polymerizing Monomers Mainly Comprising Propylene: [??]B The intrinsic viscosity [??]B of the propylene-based polymer portion (B) obtained by polymerizing monomers mainly comprising propylene was determined by measuring the intrinsic viscosity [??]A of the propylene-ethylene random copolymer portion (A) and the intrinsic viscosity [??]T of the whole propylene-based polymer.