A flexible cable is provided. The flexible cable includes a first insulation part, a second insulation part disposed on the first insulation part, a first group of ground parts disposed at regular intervals under the first insulation part, at least one transmission line disposed at regular intervals under the first insulation part and alternately arranged with the first group of ground parts, an air gap formed under the first insulation part, a prepreg layer disposed under the first insulation part, and a third insulation part disposed under the air gap and the prepreg layer. The air gap is configured to prevent signals emitted from the at least one transmission line from propagating in a direction of the air gap. Hence, it is possible to shield electromagnetic interference with other electronic components while minimizing the signal loss.