A molten steel refining method includes throwing a powder to molten steel while heating the powder with a flame formed by combustion of a hydrocarbon gas at the leading end of a top blowing lance. The lance height of the top blowing lance (the distance between the static bath surface of the molten steel and the leading end of the lance) is controlled to 1.0 to 7.0 m, and the dynamic pressure P of a jet flow ejected from the top blowing lance calculated from equation (1) below is controlled to 20.0 kPa or more and 100.0 kPa or less. P=ρg× U2/2 . . . (1) wherein P is the dynamic pressure (kPa) of the jet flow at an exit of the top blowing lance, ρg the density (kg/Nm3) of the jet flow, and U the velocity (m/sec) of the jet flow at the exit of the top blowing lance.