WIRE HARNESS INSTALLATION STRUCTURE

A wire harness installation structure includes a wire harness, a protector, and a bending motion mechanism that causes the wire harness to make a bending movement. The wire harness has a first portion that is fixed to the protector, a second portion that is distant from both of the first portion and the protector beyond a bending position of the wire harness, and a third portion that is located between the first portion and the second portion. The second portion and the third portion of the wire harness are fixed on a movable member of the bending motion mechanism, and the wire harness is routed so that a second excess length between the second portion and the third portion is shorter than a first excess length between the first portion and the third portion.