Encapsulating material for solar cell and solar cell module

An encapsulating material for solar cell comprising an ethylene/α-olefin copolymer satisfying the following requirements (a1) to (a4) and (a6):

• (a1) the content ratio of structural units derived from ethylene is from 80 to 90 mol % and the content ratio of structural units derived from α-olefin having 3 to 20 carbon atoms is from 10 to 20 mol %;
• (a2) MFR is from 10 to 50 g/10 minutes as measured under the conditions of a temperature of 190 degrees centigrade and a load of 2.16 kg in accordance with ASTM D1238;
• (a3) the density is from 0.865 to 0.884 g/cm3 as measured in accordance with ASTM D1505;
• (a4) the shore A hardness is from 60 to 85 as measured in accordance with ASTM D2240;
• and
• (a6) the content of aluminum element in said ethylene/α-olefin copolymer is from 10 to 500 ppm.