PURPOSE: To provide the titled formed article having specific intrinsic viscosity and polyene content, exhibiting plural crystal melting endothermic peaks measured by a differential scanning calorimeter in restraint state, having novel crystal melting characteristic and high strength, heat-resistance and crepe resistance.

CONSTITUTION: The objective formed article is a molecular oriented formed article of an ultra-high mol. wt. polyethylene-polyene copolymer having an intrinsic viscosity [η]of ≥5dl/g and a polyene content of 0.01W15 on an average per 1,000 carbon atoms. and produced by copolymerizing ethylene and a polyene (e.g. 1,5-hexadiene) in the presence of a Ziegler catalyst in a polymerization solvent such as n-decane, spinning the copolymer through a spinning die of a melt extruder under melting and drawing the spun fiber. The formed article exhibits two or more crystal melting endothermic peaks when measured by a differential scanning calorimeter in restraint state and one or more crystal melting endothermic peaks Tp at temperatures higher than the crystal melting temperature Tm by ≥20°C (the Tm being the characteristic melting temperature of the copolymer determined as the main melting endothermic peak in the second temperature raising process). The ratio of the calorific value caused by the crystal melting endothermic peak Tp to the total melting heat is ≥15%.