To prevent stress from being concentrated on a wire harness routed from a vehicle body to a slide door.

A wire harness laid from the vehicle body to the slide door is wrapped by a caterpillar-like cable guide formed by connecting link members one by one, and tensile force loading means is provided at at least one end in the longitudinal direction of the cable guide or the intermediate part in the longitudinal direction thereof in connection with the link members. The tensile force loading means includes a fixed material fixed to the link member at the tip of the cable guide or the link member at the intermediate portion of the cable guide, a movable material movably mounted to the fixed material, and a spring stretched between the fixed material and the movable material. The fixed material and the movable material include through holes for inserting the wire harness, the wire harness movably inserted in the through hole of the fixed material is inserted in the through hole of the movable material, the wire harness is fixed to a mounting piece protrusively provided on the lead-out side of the movable material, and tensile force by the spring is thereby loaded to the wire harness.