A continuous casting device for steel of the present invention includes a casting mold for casting a molten steel, a submerged entry nozzle, an electromagnetic stirring device, and an electromagnetic brake device. Further, a curved portion which is curved toward the electromagnetic stirring device is formed at least at a position where the curved portion faces the submerged entry nozzle, on each of the long side walls. Moreover, the horizontal distance between a top of the curved portion and the submerged entry nozzle in plan view is equal to or more than 35 mm and less than 50 mm.