A flame-retardant polyester decorative sheet according to one embodiment of the present invention comprises: a core layer comprising a polyester resin and a polyphosphonate; and a skin layer, which is positioned on at least one surface of the core layer and contains a polyester resin and a polyphosphonate, wherein the content of a color master batch in the skin layer is greater than that in the core layer, thereby solving a discoloration problem caused by a fire retardant agent while satisfying Flame Retardant Performance Standards of Notification No. 2019-2 of the National Fire Agency, and thus a flame-retardant polyester decorative sheet, which has a color tone deviation equal to that of a conventional decorative sheet product using no fire retardant agent, can be provided.