To provide a method for producing steel where the generation in the defect of microcavities can be effectively reduced even in the case of a thick plate product, further, the generation in central segregation is prevented, and the generation of the defect in a UT (Ultrasonic Test) can be eliminated as much as possible.

When steel satisfying the relation in the inequality (1); 0.2≤(W/W0)≤0.5, wherein W0(mm) is the thickness of the cast slab before the rolling-down and W(mm) is the product thickness of the steel after the hot rolling, is produced by a method where a cast slab in which a nonsolidified part is present at the inside is continuously cast as being rolled-down by rollers, and is further hot-rolled, on the rolling-down at the time of the continuous casting, it is started from a position at which the solid phase ratio at the central part of the cast slab reaches 0.4 to 0.6, and further, the rolling-down gradient is controlled, so as to be 0.7 to <4.0 mm/min on the rolling-down.