The invention provides an ethylene-.alpha.-olefin copolymer which is
superior in extrusion molding processability. The present invention is to
provide a copolymer of ethylene and .alpha.-olefin of from 4 to 20 carbon
atoms, having melt flow rate of from 1 to 100 g/10 min, an activation
energy for melt flow of 60 kJ/mol or more, melt tension at 190.degree. C.
(MT), intrinsic viscosity ([.eta.]) and a chain length A which satisfy
the formula (1) to (3), wherein the chain length A is a chain length at
peak position of a logarithm normal distribution curve of a component
having the highest molecular weight among logarithm normal distribution
curves obtained by dividing a chain length distribution curve obtained by
gel permeation chromatography measurement into at least two logarithm
normal distribution curves.