Abstract: A cable tray comprising a cover plate, side plates arranged opposite to each other, the one of said side plates being provided with openings at its lower side, supporting frames of which both ends are inserted into the openings and means for fixing every several supporting frames to the side plates. The lower end of each of said side plates is bent outwards and at right angle to form a supporting face, of which outer end is further bent upwards to form an engaging face. Said openings are arranged to have a certain distance in the longitudinal direction of the side plate and corresponding to those provided at the lower side of the other of said side plates. The upper end of each of said side plates is bent outwards and at right angle to form a flange, on which the side portion of the cover plate is overlapped, and these overlapped cover plate and flange are sandwiched between the pressing faces of a fastening means.