A plastic optical fiber comprising a core and a cladding, wherein the cladding comprises at least one layer, and the cladding comprises a copolymer which comprises 10 to 35% by weight of ethylene, 45 to 69% by weight of tetrafluoroethylene, 20 to 45% by weight of hexafluoropropylene, and 0.01 to 10% by weight of a fluorovinyl compound represented by Formula (1): CH2═CX1(CF2)nX2 (wherein X1 represents a fluorine atom or a hydrogen atom, X2 represents a fluorine atom, a hydrogen atom, or a hydrocarbon group, and n represents an integer from 1 to 10) as a copolymer component.