Cable duct, electronic device system, cable duct system, and method for replacing housing in electronic device system

A cable duct system disposed over top plates of a plurality of housings each of which contains an electronic device, the cable duct comprising: a first cable duct that includes: a first bottom plate (30) that is disposed over the top plate of a first housing containing a first electronic device (1b), has a first front side and a first lateral side, and includes, at the first front side, a first cut-out part (31) through which a cable (9) from the first electronic device (1 b) is inserted; and a first lateral plate (40) that is provided so as to stand on the first lateral side and that includes a first window (41) through which the cable (9) from the first electronic device (1 b) can be inserted; a second cable duct (20) that includes: a second bottom plate (30) that is disposed over the top plate of a second housing containing a second electronic device (1 a), has a second front side and a second lateral side, and includes, at the second front side, a second cut-out part (31) through which a cable (9) from the second electronic device (1 a) is inserted; and a second lateral plate (50) that is provided so as to stand on the second lateral side and that includes a second window (51) through which the cable (9) from the second electronic device (1a) can be inserted; and a first bridge (90) that bridges between the first window (41) and the second window (51) and is configured so that the cable (9) from the first electronic device (1 b) and the cable (9) from the second electronic device (1 a) can be inserted therethrough.