NOVELTY - A plastic molded product is obtained using crystalline norbornene monomer ring-opened polymer hydrogenated substance which is cross-linked. The crystalline norbornene monomer ring-opened polymer is obtained by performing ring-open-polymerization reaction of polymerizable monomer containing 2-norbornene and substituent-containing norbornene and hydrogenation process. The ring-opened polymer hydrogenated substance has molecular weight of 50000-200000 measured by gel permeation chromatography, melting point of 110-145 degrees C and hydrogenation rate of 80% or more.    USE - Plastic molded product e.g. resin film and sheet. Uses included but are not limited to food packaging bags for processed foods such as ham, sausage, retort food, frozen food, dried food, cooked rice, confectionery and meat, bag for infusion solution, bag for infusion, solar energy power generation system energy strip, fuel cell edge strip, alcohol-containing fuel-system material, barrier film, retardation film, polarizing film, light-diffusion sheet and light-condensing sheet.    ADVANTAGE - The molded product has excellent steam barrier property, heat resistance, oil resistance, mechanical characteristic, solvent resistance, transparency and workability.    DETAILED DESCRIPTION - A plastic molded product is obtained using crystalline norbornene monomer ring-opened polymer hydrogenated substance which is cross-linked. The crystalline norbornene monomer ring-opened polymer is obtained by performing ring-open-polymerization reaction of polymerizable monomer containing (in wt.%) 2-norbornene (90-100) and substituent-containing norbornene (10-0) and hydrogenation process. The crystalline norbornene monomer ring-opened polymer has molecular weight of 50000-200000 measured by gel permeation chromatography, melting point of 110-145 degrees C, hydrogenation rate of 80% or more and ratio of weight average molecular weight and number average molecular weight of 1.5-10.0. The molded article is irradiated by active energy ray of 100-500 kGy.