A cable support mechanism has a cable support portion, and supports two flexible cables which are ribbon-shaped and in each of which a plurality of conductors are arranged in parallel to each other in a coating material. The cable support portion includes a first support surface, a second support surface, and a plurality of guide ribs. The first support surface supports one of the two flexible cables. The second support surface is formed on a side reverse to a side where the first support surface is formed, and supports the other one of the two flexible cables. The guide ribs projects from two edges of each of the first support surface and the second support surface, the two edges opposing each other in a flexible-cable width direction, so as to overlap, and be spaced by a predetermined distance from, the first support surface and the second support surface.