A wire harness fixing structure includes a plate-like member including a first layer and a second layer softer than the first layer, an electrical wire disposed along the plate-like member, and a fixing member attached to the electrical wire to fix the electrical wire to the plate-like member. The fixing member includes: a through locking piece formed to be able to pass through the first layer and locked to the first layer while passing through the first layer, a regulation piece provided with a space between the regulation piece and the through locking piece to stop the through locking piece from passing through a surface of the plate-like member, and a column connecting the through locking piece and the regulation piece.