A blast furnace operation method in which reducing gas including hydrogen atoms and carbon atoms is blown into a blast furnace, the method comprising: acquiring a correlation between a carbon consumption in the reducing gas and a reduction InputΔC by performing calculation using various cases where C/H in the reducing gas and the amount of the reducing gas blown are different from each other, wherein the InputΔC is defined as the proportion of reduction in specific carbon consumption Input C of an operation where a predetermined amount of reducing gas is blown with respect to a base operation where the reducing gas is not blown, and the Input C refers to the total mass of coke, pulverized coal, and carbon in the reducing gas for producing one ton of molten iron; determining a carbon consumption in the reducing gas where the reduction InputΔC in specific carbon consumption is a predetermined target value of the reduction InputΔC or higher on the basis of the correlation between the carbon consumption in the reducing gas and the reduction InputΔC acquired per C/H; and adjusting an amount of the reducing gas blown into the blast furnace on the basis of the determined carbon consumption in the reducing gas and a carbon proportion in the reducing gas, wherein the molar ratio C/H of the carbon atoms to the hydrogen atoms in the reducing gas is 0.15 or higher, wherein the carbon consumption in the reducing gas is determined in a range of 21 kg/t-pig to 107 kg/t-pig, and wherein the carbon consumption in the reducing gas is a value obtained by multiplying the carbon proportion kg/Nm 3 in the reducing gas by the reducing gas volume Nm 3 /t-pig per ton of molten iron. acquiring a correlation between a carbon consumption in the reducing gas and a reduction InputΔC by performing calculation using various cases where C/H in the reducing gas and the amount of the reducing gas blown are different from each other, wherein the InputΔC is defined as the proportion of reduction in specific carbon consumption Input C of an operation where a predetermined amount of reducing gas is blown with respect to a base operation where the reducing gas is not blown, and the Input C refers to the total mass of coke, pulverized coal, and carbon in the reducing gas for producing one ton of molten iron; determining a carbon consumption in the reducing gas where the reduction InputΔC in specific carbon consumption is a predetermined target value of the reduction InputΔC or higher on the basis of the correlation between the carbon consumption in the reducing gas and the reduction InputΔC acquired per C/H; and adjusting an amount of the reducing gas blown into the blast furnace on the basis of the determined carbon consumption in the reducing gas and a carbon proportion in the reducing gas, wherein the molar ratio C/H of the carbon atoms to the hydrogen atoms in the reducing gas is 0.15 or higher, wherein the carbon consumption in the reducing gas is determined in a range of 21 kg/t-pig to 107 kg/t-pig, and wherein the carbon consumption in the reducing gas is a value obtained by multiplying the carbon proportion kg/Nm 3 in the reducing gas by the reducing gas volume Nm 3 /t-pig per ton of molten iron.