A compressor having a rotor. The rotor comprises a core formed as a plurality of laminates are vertically stacked one above another and magnets provided on the outer circumference of the core. Hooks are integrally formed on the outer circumference of the core between the respective magnets in order to prevent outward separation of the magnets. For this, a respective one of the hooks includes a protruding portion extending outward from the core in a radial direction, and a support portion extending from a distal end of the protruding portion in a circumferential direction. The protruding portion serves to keep the magnets spaced apart from one another, and the support portion serves to prevent the magnets from being separated in a radial direction.