a chassis that includes at least a bottom plate of an enclosure having a box-shaped outer shell;

a stay that holds a motherboard perpendicularly with respect to the bottom plate;

guide members that are provided with slots for guiding a substrate unit to be perpendicularly plugged into the motherboard by way of a connector, the guide members being disposed on both sides for guiding the substrate unit, and being configured to pull out integrally with the motherboard towards a plug-in side from which the substrate unit is plugged in;

a cover that includes at least a top cover side of the enclosure except for a portion corresponding to the bottom plate and a portion corresponding to the plug-in side;

a panel attached to a position between the guide members corresponding to the substrate unit, the panel individually covering a plug-in section of the substrate unit;

a front cover formed to edge around the panel and attached to the enclosure from outside the panel;

a sealing plate disposed on one of the guide members located at an insertion end side, opposite the motherboard, the sealing plate preventing insertion in a direction crossing one of the guide members; and

a notch formed at a position corresponding to the sealing plate located closer to the front cover, the notch establishing mutual communication between an inside and an outside of the enclosure,

wherein the panel is provided with an opening that allows, when a communication cable is connected to the substrate unit to be connected to the motherboard from the front cover side, viewing of a connecting terminal into which a jack of the communication cable is to be plugged, and

wherein when a communication cable extending from the substrate unit connected to the motherboard is drawn to the outside of the enclosure in a direction crossing the plug-in direction of the substrate unit, the communication cable is wired so as to cross over one of the guide members and the notch in a state in which the sealing plate is removed.