(1) As illustrated in FIG. 9, in the server apparatus S, after cable units 50 are mounted to the rack 10, front-face side and back-face-side electronic units 40 are mounted to the rack 10 such that the front-face side and the back-face-side electronic units 40 are able to be connected by the cables 63. Accordingly, an operation to connect the electronic units 40 by the cables 63 is unnecessary in a state in which the electronic units 40 have been mounted to the rack 10. Thus, working space can be reduced and the wiring space for the cables 63 can be reduced. As a result, space savings can be achieved and the transmission distance between electronic units 40 can be shortened, enabling high-density mounting of the electronic units 40 and high speed transmission between electronic units 40 to be realized.