To provide a technique which investigates causality between the occurrence of powder entrapment and electromagnetic stirring in the casting of a bloom or a billet accompanied by electromagnetic stirring, and prevents the occurrence of powder entrapment.

A continuous casting method for superclean steel is disclosed by which a bloom or a billet having a carbon content C [wt.%] of 0.4 to 0.8, a silicon content Si [wt.%] of 0.2 to 2.5 and a manganese content Mn [wt.%] of 0.2 to 1.2 is subjected to continuous casting accompanied by electromagnetic stirring applying horizontal swirling properties to molten steel in a mold, and the method is performed in such a manner that electromagnetic stirring intensity MEMS [gauss] in the mold as the intensity of the electromagnetic stirring, the radius rSN [mm] in the powder line part of an immersion nozzle and the thickness D [mm] of the mold satisfy expression (1) or (2).