An ethylene-α-olefin copolymer wherein the copolymer has a monomer unit based on ethylene and a monomer unit based on an α-olefin having 3 to 20 carbon atoms, the density (d) is 860 to 950 kg/m3, the melt flow rate (MFR) is 1 to 100 g/10 min, the flow activation energy (Ea) is 60 kJ/mol or more, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 5.5 to 30, the ratio (Mz/Mw) of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) is 2 to 5, and the swell ratio (SR) is 1.55 or more and less than 1.8.