TECHNOLOGY FOCUS - POLYMERS - Preferred Material: The solar cell sealing material has volume resistivity of 1x 1013-1x 1018 Omega .cm measured at 100 degrees C and applied voltage of 500V based on JIS K6911. The solar cell sealing material further contains (in parts weight) silane coupling agent (0.1-5) and crosslinking agent (0.1-2.5) with respect to ethylene- alpha -olefin-nonconjugated-polyene copolymer (100). The crosslinking agent is an organic peroxide having half life temperature of 100-170 degrees C for 1 minute. The solar cell sealing material further contains at least 1 type of a ultraviolet absorber, a heat-resistant stabilizer, and a hindered amine-type optical stabilizer (0.005-5), and crosslinking adjuvant (0.05-5) with respect to ethylene- alpha -olefin-nonconjugated-polyene copolymer (100). The ethylene- alpha -olefin-nonconjugated-polyene copolymer has B value of 0.9-1.3 calculated from 13C-nuclear magnetic resonance spectrum and from formula: B=(c+d)/(2x ax (e+f)), where a is ratio (ethylene molar fraction) of structural unit (a1) contained in copolymer, c is ratio (ethylene- alpha -olefin dyad molar fraction) of the structural unit of ethylene- alpha -olefin linkage, d is ratio (ethylene and nonconjugated polyene dyad molar fraction) of structural unit of ethylene and nonconjugated polyene linkage, e is ratio ( alpha -olefin molar fraction) of structural unit derived from alpha -olefin, and f is ratio (nonconjugated polyene molar fraction) of structural unit derived from nonconjugated polyene. The ratio of maximum value (Pmax) of ethylene distributed parameter (P) calculated from gel permeation chromatography-offline-Fourier transform infrared spectroscopy and minimum value (Pmin) of copolymer is 1.4 or less. The copolymer has flow activated energy of 28-45 kJ/mol, molecular weight distribution of 1.2-3.5 based on gel permeation chromatography (GPC), chloride ion content of 2 ppm or less detected from extract after solid phase extraction process by ion chromatography, and extract amount of 5 wt.% or less with respect to methyl acetate. The solar cell sealing material is sheet-form material. The solar cell sealing material is obtained by molding the ethylene- alpha -olefin-nonconjugated-polyene copolymer and an additive in a calender molding in a sheet form after melt-kneading. The solar cell sealing material is formed using resin composition containing ethylene- alpha -olefin-diene copolymer having 50-95 mol% of structural unit derived from ethylene, and Mooney-viscosity (ML(1+4)100 degrees C) is 30-90, paraffinic oil having paraffin component content of 55-90 weight%, aroma component of less than 5 weight%, naphthene component of less than 40 weight%, and sulfur component content of 200 ppm or less, and crosslinking agent. The resin component has melt flow rate of 2-10 g/10 minutes at 190 degrees C and load of 2.16 kg. The melting point of copolymer according to JIS-K7121 is 70 degrees C or less. The light transmittance of the hardened material of the solar cell sealing material is 90% or more. The solar cell sealing material further contains at least 1 type of additive chosen from a crosslinking adjuvant, a ultraviolet absorber, weathering stabilizer, antioxidant, and an adhesive imparting agent. The temperature of the calendering roll in calender molding is 55-110 degrees C.