<p>An arm structure includes a first arm (5) pivotally supported on a body, and a second arm (6) pivotally supported on the first arm at an axis portion formed on a distal end side of the first arm. A wire harness fixing portion (8) for fixing a wire harness (11) is provided at a distal end side (12) of the second arm. A guide portion having a curved face for guiding the wire harness is provided at an end portion at an end side of the second arm, the end side being opposite to the distal end side. A width of the guide portion is larger than a width of a portion of the second arm corresponding to the axis portion, in a width direction perpendicular to a longitudinal direction of the second arm.</p>
