Method for producing molten iron having low phosphorus content

It is an object of the present invention to carry out an effective dephosphorization treatment by adding small amount of refining agent without adding large amount of CaF2. The present invention found out that extremely effective dephosphorization using inhomogeneous molten state of slag is made possible by supplying oxygen gas and refining agent in the specified form into surface of molten bath under a condition that the amount of slag after the treatment is considerably reduced in comparison with the prior arts. The dephosphorization is carried out by blowing the oxygen gas and at least a part of the refining agent through top blowing lance onto the surface of the molten bath. The amount of slag after the treatment is 30 kg/ton of molten iron or less, preferably 20 kg/ton of molten iron or less, more preferably 10 kg/ton of molten iron or less. Moreover, the dephosphorization is preferably subjected to molten iron of 0.15 mass % or less Si, more preferably 0.07 mass % or less Si, most preferably 0.03 mass % or less Si.