As illustrated in FIGS. 2 and 6, the first end plate 40a is disposed to face an end surface on one end side in the axial direction of the rotor core 20. An insertion hole 41 through which the rotor shaft 10 is inserted is formed in the center of the first end plate 40a. In a portion further on the outer side in the radial direction than the insertion hole 41, a plurality (six in the present embodiment) of first refrigerant discharge holes 42a are formed at equal intervals in the circumferential direction to overlap the second refrigerant flow path holes 26 formed in the rotor core 20 when viewed from the axial direction. That is, the first refrigerant discharge hole 42a communicates with the second refrigerant flow path hole 26.

On an inner surface of the first end plate 40a, an annular refrigerant introduction groove 43 communicating with the refrigerant flow path 12 formed in the rotor shaft 10 at the inner diameter side corner portion of the insertion hole 41 and an annular first groove portion 44a communicating with the refrigerant introduction groove 43 and communicating with the first refrigerant flow path hole 25 of the rotor core 20 are formed.