Disclosed is a private branch exchange (PBX) that offers high efficiency in wiring cables, at the same time, protects cables in highly safety manner. The PBX includes a PBX section and a casing that covers and holds the PBX section. The casing contains an inner-bottom plate, a support column, and a pedestal. Cables for connections with external circuitry can be connected to the PBX section on the front side of the interior of the casing. The inner-bottom plate holds the bottom of the portion of the casing on which the PBX section is accommodated. The support column is disposed on the lower surface of the inner-bottom plate. Disposed beneath the support column, the pedestal holds the entire of the casing. The support column has a curved surface on the front side, protecting cables wired between the inner-bottom plate and the pedestal.