In a wire harness routing structure, a main link arm supports a door main body to be slidable with respect to a vehicle body while relatively rotating with respect to each of the vehicle body and the door main body. A sub-link arm supports the door main body to be slidable with respect to the vehicle body together with the main link arm while relatively rotating with respect to each of the vehicle body and the door main body. A first wiring line is provided to be routed along the main link arm, and connects a vehicle body-side connector on the vehicle body side and a door-side connector on the door main body side. A second wiring line is provided to be routed along the sub-link arm and connects the vehicle body-side connector on the vehicle body side and a second door-side connection target on the door main body side.