a harness body having a first routing portion routed in a link mechanism that couples a vehicle body and a slide door and reciprocates the slide door in a sliding direction with respect to the vehicle body, a second routing portion routed closer to a side of the vehicle body than the first routing portion, and a third routing portion routed closer to a side of the slide door than the first routing portion;

a harness fixing tool that fixes a fixing portion of the third routing portion to a fixed portion on the side of the slide door provided not to cause relative displacement with respect to the slide door; and

a harness guide tool that regulates a routing path of the third routing portion, wherein

the link mechanism includes a first arm member having one end portion coupled to the side of the vehicle body and the first routing portion routed to the other end portion, a second arm member having one end portion connected to the side of the slide door, a first rotation shaft having a direction orthogonal to the sliding direction as an axial direction and capable of first relative rotation between the vehicle body and the one end portion of the first arm member, a second rotation shaft parallel to the first rotation shaft and capable of second relative rotation between the other end portion of the first arm member to which the harness guide tool is fixed and the other end portion of the second arm member, and a third rotation shaft parallel to the first rotation shaft and the second rotation shaft and capable of third relative rotation between the slide door and the one end portion of the second arm member, in which the slide door reciprocates in the sliding direction with respect to the vehicle body along a plane orthogonal to the first rotation shaft, the second rotation shaft, and the third rotation shaft,

the harness guide tool guides the third routing portion toward the fixed portion on the side of the slide door positioned in a direction intersecting the orthogonal plane with respect to the harness guide tool, and

the fixed portion on the side of the slide door is provided on a plane where an axis center of each of the second rotation shaft and the third rotation shaft exists and in the direction intersecting the orthogonal plane with respect to the harness guide tool when a relative rotation position of the second arm member about an axis of the third rotation shaft with respect to the slide door is a central position of a swing width of the third relative rotation.