A device which rotatably supports a circular drum (10) wound by a cable include a main body (20); a rotation support part (30) which has a pair of support rollers (31)(32) to induce the rotation of the drum (10) on the upper side of the main body (20); and a separation preventing part (40) which has a pair of guide roller (41)(42) from the upper side of the main body (20) to the outside of the rotation support part (30). Thereby, in a release process of a cable wound around a cable drum in installing a vessel, the turnover of the drum can be prevented. Stable support is carried out by the structure of a turning roller type.
