To provide a molten magnesium supply pump having the high molten metal supply accuracy.

A vane type molten metal supply pump 106 transports molten magnesium 114 stored in a vessel 104 to a runner pipe 102. A control unit 120 changes the number of revolutions of a rotor according to the level of the molten magnesium 114 in the vessel 104. The control unit 120 performs the intermittent operation of alternately repeating the operation period for rotating the rotor and the stop period of stopping the rotor for the predetermined period, and increases the number of revolutions of the rotor for each operation period. The control unit 120 determines the number of revolutions N so as to satisfy Δh=a×N2+b (where, a and b denote parameters of real number) when the difference between the molten metal level H as the reference and the present molten metal level h is Δh.