Process for preparing a composition for preparing a polyolefin series resin film and process for preparing the film

The polyolefin [A] has a weight average molecular chain length of 2850nm or longer and a density ρ1 (g/cm3), the polyolefin wax [B] has a weight average molecular weight of 700-6000 and a density ρ2 (g/cm3), the polyolefin and the polyolefin wax are incorporated at [A]/[B]=90/10-50/50 (ratio by weight), and the densities ρ1 and ρ2 satisfy the following conditions:0.92≤ρ1≤0.94, 0.91≤ρ2≤0.93, -0.03≤(ρ1-ρ2)≤0.03.