Similarly, the second positioning pins 101 are provided to the second positioning panel 92. In addition, the second positioning holes 26, into which the second positioning pins 101 are inserted, are formed in the second fixing portion 25 of the rack 10. Accordingly, the second positioning pins 101 are inserted into the second positioning holes 26 when the second back panel unit 90 is inserted into the rack 10, enabling the second back panel unit 90 to be positioned relative to the rack 10. This enables the ease of an operation to mount the second back panel unit 90 to the rack 10 to be improved.

Explanation follows regarding modified examples of the present exemplary embodiment.

(1) As illustrated in FIG. 1, etc., although the cable units 50 are applied to a server apparatus S, the cable units 50 may be applied to electronic apparatuses other than the server apparatus S.

(2) As illustrated in FIG. 5 and FIG. 6, the upper wall and the pair of side-walls of the second peripheral side-walls 57 formed to the second casing body 53 are disposed at the outside of the upper wall and the pair of side-walls of the first peripheral side-walls 55 formed to the first casing body 52. However, the upper wall and the pair of side-walls of the second peripheral side-walls 57 formed to the second casing body 53 may be disposed at the inside of the upper wall and the pair of side-walls of the first peripheral side-walls 55 formed to the first casing body 52.