To provide a method for manufacturing a sound steel block of small center segregation, using a small dead-head volume and under the same workability as before.

In manufacturing a forging steel block by congealing a molten metal pored in a block making mold A composed of a mold 2 and a dead-head frame 3, a dead-head 6 diameter (D) formed by the dead-head frame is set against a top face inner diameter (D1) of the mold as D/D1=0.5-0.8, also, a dead-head height (H) is set against the dead-head diameter (D) as H/D=0.6-0.9, and the dead-head ratio is set 9-12% respectively.