A polyethylene terephthalate composition includes a copolymer component having at least 3 functional groups in an amount of 0.01 mol % to 1.00 mol % with respect to ethylene terephthalate units, in which a ratio (Mw/Mn) between the weight average molecular weight and number average molecular weight of the polyethylene terephthalate composition is 5.0 to 8.0; an alkali metal compound in an amount of 1.0 mol/ton to 3.0 mol/ton in terms of alkali metal element; a phosphorus compound in an amount of 1.5 mol/ton to 5.0 mol/ton in terms of elemental phosphorus; and an o-chlorophenol insoluble matter in an amount of less than 0.5 wt %.