To prevent a break in a cable even when a cable holder is repeatedly bent and unbent.

An introducing and holding portion is formed on both sides of a long plate-like elastic body portion, and a cable supporting portion is formed between the introducing and holding portions. Each of the introducing and holding portions includes: an introducing opening; an introducing cut portion extended to the introducing opening; and a curved portion adjoining to the introducing opening and the introducing cut portion. The cable supporting portion includes: a supporting opening; a pair of supporting cut portions formed at each end of the supporting opening so that they are extended toward the respective introducing and holding portions; and a supporting piece formed between each pair of the supporting cut portions. A device fixed portion is provided at one end of the body portion in the direction of length, and is rotatably fixed on a inner wall of a device rack. A shelf board fixed portion is provided at the other end of the body portion in the direction of length, and is rotatably fixed on the back of a movable shelf board.