A composite vinylidene chloride copolymer resin composition having excellent processability and composed of a vinylidene chloride copolymer resin composition A having a molecular weight of 50-300 thousand and another vinylidene chloride copolymer resin composition B having a molecular weight which is 5 thousand or above but is less than a value whichever is lower between 0.8 multiplied by the weight-average molecular weight of the composition A and 80 thousand; and a monolayer film produced from the composite composition, being excellent in barrier properties, nonextractability with oleaginous food and high-frequency sealability, and being useful as barrier packaging material for ham, sausage and other foods, and as wrapping film.