In an arrangement in accordance with the invention for attaching a permanent magnet to an electrical machine's rotor, the rotor comprises at least two magnetic poles, and there is a pole gap between two magnetic poles. Permanent magnets are installable on the surface of the magnetic core. A pole piece is installable on the permanent magnet side facing the air gap. There is fixing means on the sides of the pole piece facing the pole gap for attaching the pole piece to the rotor using the locking parts, and the fixing means are connected to the pole piece through an articulated joint.