Abstract: The cable support block is for temporarily supporting a lower cable to an upper aerial cable. The support block comprises a rigid arcuate frame having an upper yoke straddling the upper cable, and an idle load-bearing roller rotatably mounted on the frame and supporting the lower cable. An elongated coil spring is fixedly attached at a first end thereof to the frame and defines a second opposite free end portion thereof movable relative to the first end by resilient: deformation of the coil spring. To insert a cable into the arcuate frame, the cable is forcibly abutted against the coil spring which will resiliently yield to allow access of the cable into the arcuate frame by being inwardly deformed.