To restrain the heat variation and the reaction variation in a blast furnace, to reduce the heat loss and to restrain the irregular level-down of raw material in the furnace by blending coal so as to have an allowable volatile matter content or below according to the pulverized coal ratio and injecting into the blast furnace.

The pulverized coal is injected together with hot blast from a blasting tuyere in a blast furnace. In this blast furnace operation, the coal is blended so that the allowable volatile matter content in the pulverized coal becomes not more than the quantity regulated in the equation; the allowable volatile matter content (%)=-0.2×(PC/R)+60 and injected into the blast furnace. Wherein, PC/R(pulverized coal ratio)=the pulverized coal quantity (kg/hr)/ iron tapping quantity (pig ton/hr). In this way, the heat level variation and the reaction variation in the blast furnace can be restrained. Further, in the case of using single or plural coal kinds, the increase of the heat loss and the irregularity of level-down of the raw material in the blast furnace caused by the increase of generated gas in the blast furnace can be restrained, too.