A casting nozzle suited to manufacture a casting material of pure magnesium or magnesium alloy is provided. A nozzle is utilized to manufacture a casting material by supplying molten metal to a portion between rolls which become a casting die, and arranged so that a pouring port is located between a pair of rolls opposed to other. This nozzle includes a main body formed of oxide material such as alumina, and a coating layer which is provided on the inner surface of the main body which comes into contact the molten metal, and formed of material that does not include oxygen substantially. Since the main body does not come into direct contact with the molten metal due to the coating layer, it is possible to prevent oxygen included in the main body from reacting with the molten metal. Further, in the nozzle, a casting die contact portion which comes into contact with the rollers is formed of thermal insulation material, whereby it is prevented that the molten metal in the nozzle is cooled through the casting die contact portion by the rollers.