A binding structure of wire routing materials are formed by: elongated wire routing materials; a binding member for binding the wire routing materials; and an engaging member including a movable body portion including an engaging portion for assembly into a vehicle body, and a bound portion to be bound and held together with the wire routing materials by the binding member. The bound portion includes a main portion facing the wire routing materials, and a leg portion extending from the main portion and being in contact with the wire routing materials. The movable body portion includes a sliding portion disposed such that sliding thereof is allowed on the wire routing materials in a gap.