To obtain a resin material which does not emit any toxic gases, has good molding stability and can give utrathin films having good cuttability, transparency, adhesion, etc., and a low sheet break rate by using a low-density polyethylene resin having a specified density, a specified melt flow rate, and a specified molecular weight distribution and obtained by a high-pressure radical polymerization process.

The low-density polyethylene resin used has a density of 0.910-0.935 g/cm3, a melt flow rate of 1.0-10 g/10 min, and a molecular weight (Mw/Mn) of 3.0-4.5. An ultrathin film obtained from this material has a thickness of 7-20 μm and a tensile impact strength of 850 kgf.cm/cm2 or above (in the machine direction). In order to further improve the adhesion, it is desirable to add an aliphatic polyhydric alcohol (e.g. glycerol) and a fatty acid ester (e.g. glycerol oleate). It is also possible that the material is further compounded with an inorganic or organic filler. In addition to a single-layer ultrathin film, a laminate structure ultrathin film can also be obtained.