Abstract: An electric supercharger includes: a shaft including a small diameter portion, a large diameter portion having a larger diameter than that of the small diameter portion, and a step surface extending in a radial direction from an outer circumferential surface of the small diameter portion to an outer circumferential surface of the large diameter portion; a rotor core in which one end surface of a main body portion through which the small diameter portion is inserted abuts against the step surface, the rotor core formed with, in the main body portion, a receiving hole that is opened to the end surface; a magnet accommodated in the receiving hole; and an end plate inserted with the large diameter portion and facing at least a part of the magnet accommodated in the receiving hole.