The invention relates to a signalling device (1) for an aerial transmission line (2) comprising two signalling elements (3, 4) which are configured to be mounted one against the other around a conductor portion (2) of the transmission line, in which at least one of the two signalling elements (3, 4) comprises at least partially an outer signalling coating in the context of air safety, which device is characterized in that the two signalling elements (3, 4) are at least partially electrically conductive and at least one of the two signalling elements (3, 4) comprises a clamping means (5) which is configured to clamp the conductor portion (2) of the transmission line. The invention also relates to a method for assembling such a device on a high-voltage aerial transmission line.
