A cooling drum for a twin-drum continuous casting machine is capable of ensuring an excellent drum body interior cooling effect and advantageously overcoming both the problem of wear of the cooling drum end portions that are pressure-contacted with, and slide on, the side dams and the problem of their local deformation, and that, as a result, can ensure long-term maintenance of a suitable pressure-contact sliding state between the side dams and the cooling drum so as to enable stable continuous casting over a prolonged period. The cooling drum comprises a drum body portion of a material having a thermal conductivity of 100-400 W/mK and drum end portions part or all of whose portions in pressure-contact with the side dams and/or part or all of whose inner regions are formed of a reinforcing material that is a high-hardness material having a Vickers hardness HV (250 g) of 300-600.