To provide a rotor for an IPM motor capable of reducing a loss due to magnetic distortion by reducing stress caused at a contact part between a core block and a key and the magnetic distortion caused by the stress.

A rotor 10 comprises: a rotor shaft 30 where a key groove 30k is formed at an outer peripheral surface; a core block where the key groove is formed at an inner peripheral surface; a key 50 inserted in the key groove 30k; and a contact face between the key 50 and the core block having an uneven shape.