A water-atomized metal powder is produced by dividing a molten metal stream into a metal powder by making injection water having a liquid temperature of 10° C. or less and an injection pressure of 5 MPa or more impinge on the molten metal stream and cooling the metal powder. Cooling with injection water having a liquid temperature of 10° C. or less and an injection pressure of 5 MPa or more enables can be performed not in the film boiling region but in the transition boiling region from the beginning of cooling. A gas-atomized metal powder may also be produced by dividing a molten metal stream into a metal powder by making an inert gas impinge on the molten metal stream and cooling the metal powder with injection water having a liquid temperature of 10° C. or less and an injection pressure of 5 MPa or more.