According to one embodiment, there is provided a magnetic resonance imaging apparatus in which a gradient field power supply apparatus supplies currents to gradient field coils corresponding to spatial coordinate axis directions to form gradient fields in a static field space which change along the respective spatial coordinate axis directions, the gradient field power supply apparatus includes a transformer configured to supply power supplied to a primary winding to a current output circuit via a plurality of secondary windings, with the number of phases of the primary windings being equal to or a multiple of the number of phases of the secondary windings, and the secondary windings of the respective phases of output channels corresponding to the respective spatial coordinate axis directions being wound around the primary windings of the respective phases.