The present invention is directed at: developing a fiber with which smoke emission during production of a nonwoven fabric is reduced and which is favorable in an olefin polymer nonwoven fabric that is excellent in both initial hydrophilic property and enduring hydrophilic property and developing a nonwoven fabric. The present invention is to provide a fiber comprising an olefin polymer composition including, based on 100 parts by weight of an olefin polymer, 0.5 to 5 parts by weight of a di-fatty acid ester of a poly(oxyalkylene) diol represented by formula (1) described below and 0.01 to 2.5 parts by weight of a poly(oxyalkylene) sorbitan tri-fatty acid ester (the alkylene group being ethylene, propylene or butylene group, the number of added moles being 10 to 40, and the fatty acid being an alkyl or alkylene fatty acid having a carbon number of 12 to 18). R1-COO-(CnH2nO)a-C6H12-O(CnH2nO)b-CO-R2 ··· (Formula 1) [wherein R1 and R2 represent an alkyl group having a carbon number of 11 to 17 and may be the same or different, n in (CnH2nO) a and (CnH2nO) b is an integer of 2 to 4, and a + b is 5 to 23].
