A slide door of a vehicle, the slide door comprising a power feeding wiring structure, the power feeding wiring structure comprising: (a) a protection tube; (b) a plurality of wires arranged in the protection tube; (c) a slide door side fixing device provided on the slide door and adapted to fix one end of the protection tube; and (d) a vehicle body side fixing device configured to be provided on a vehicle body and adapted to fix the other end of the protection tube; wherein: the slide door side fixing device includes: (c-1) a base portion fixed in the slide door with the protection tube arranged inside, (c-2) a restricting portion (35; 135) for restricting a moving range of the protection tube near the slide door by being pivoted about a rotary shaft relative to the base portion with the protection tube arranged inside, wherein the rotary shaft is parallel to the lateral direction of the slide door, and (c-3) a biasing portion for rotating the restricting portion (35; 135) in a biasing direction by accumulated elastic energy; and a center line along a length direction of the restricting portion (35; 135) is located in an area at a front side in the biasing direction with respect to a first plane defined by the position of a leading end (35a; 135a) of the restricting portion (35; 135) and the rotary shaft, whereby the leading end (35a; 135) of the restricting portion (35; 135) projects out from the slide door downwardly through an opening in an inner panel of the slide door when the slide door is moved to be opened and closed. (a) a protection tube; (b) a plurality of wires arranged in the protection tube; (c) a slide door side fixing device provided on the slide door and adapted to fix one end of the protection tube; and (d) a vehicle body side fixing device configured to be provided on a vehicle body and adapted to fix the other end of the protection tube; the slide door side fixing device includes: (c-1) a base portion fixed in the slide door with the protection tube arranged inside, (c-2) a restricting portion (35; 135) for restricting a moving range of the protection tube near the slide door by being pivoted about a rotary shaft relative to the base portion with the protection tube arranged inside, wherein the rotary shaft is parallel to the lateral direction of the slide door, and (c-3) a biasing portion for rotating the restricting portion (35; 135) in a biasing direction by accumulated elastic energy; and (c-1) a base portion fixed in the slide door with the protection tube arranged inside, (c-2) a restricting portion (35; 135) for restricting a moving range of the protection tube near the slide door by being pivoted about a rotary shaft relative to the base portion with the protection tube arranged inside, wherein the rotary shaft is parallel to the lateral direction of the slide door, and (c-3) a biasing portion for rotating the restricting portion (35; 135) in a biasing direction by accumulated elastic energy; and a center line along a length direction of the restricting portion (35; 135) is located in an area at a front side in the biasing direction with respect to a first plane defined by the position of a leading end (35a; 135a) of the restricting portion (35; 135) and the rotary shaft, whereby the leading end (35a; 135) of the restricting portion (35; 135) projects out from the slide door downwardly through an opening in an inner panel of the slide door when the slide door is moved to be opened and closed.