An ethylene/hexafluoropropylene copolymer which is favorable for hoses or seals for automobile engine oil and exhibits necessary and sufficient amine resistance with its resistances to heat, oil and chemicals kept near the levels of fluororubbers of the prior art. This copolymer comprises 35 to 60 mole % of ethylene structural units, 25 to 50 mole % of hexafluoropropylene structural units and 0 to 15 mole % of structural units derived from monomers copolymerizable therewith and has a fluorine content of 60 wt% or above and a number-average molecular weight of 3000 to 500000.
