The present disclosure provides a flexible illuminating flat cable structure including a connector, a circuit board, a plurality of external signal lines, a first illuminating unit, a shell, signal lines, a fiber cable, and a transparent coat. The connector connects to an electronic device. The circuit board includes contact welds, signal line welds, a first illuminating unit weld, controller welds, and an external signal line welds. The external signal lines conduct a power signal or a control signal. The controller generates a power control signal according to the power signal or the control signal sent from the external signal lines. The first illuminating unit generates lights according the power control signal. The shell includes an illuminating mark corresponding to the first illuminating unit. The signal lines transmit data signals. The fiber cable transmits lights.