There are provided a casting roll of a twin-roll strip caster and a method for manufacturing a high-nitrogen duplex stainless steel strip having no dimple. The casting roll has an average roughness Ra of 10 μm to 30 μm, and diagonal fine grooves having a width of 50 μm to 500 μm, an interval of 100 μm to 1000 μm, and a depth of 50 μm to 200 μm are formed in the casting roll. The diagonal fine grooves are symmetrically intersecting each other at an angle of 30° to 70° with respect to circumferential direction of the casting roll.