A fastening device for a line in a vehicle includes a carrier, fixing structure, and fastening element. The carrier is configured to enclose the line and includes a multi-part base body having at least two partial base bodies and an inner region. The partial base bodies are adjustable between a premounted state, whereat the partial base bodies are disengaged from each other, and a mounted state, whereat the partial base bodies are engaged with each other such that the multi-part base body fully annularly encloses the line. The fixing structure is formed on the inner region of the base body and configured, in the mounted state, to fix the carrier axially on the line. The fastening element includes a fastening structure and holder that connects the fastening element to the carrier.