A holder attaching groove (45) extending in a shaft direction is provided on an outer circumference part of a rotor core (16). In the holder attaching groove (45), a holder arm (32) having a substantially T-shaped cross section is attached. The holder arm (32) is provided with a main body part (41), a fitting protruding part (44) and a magnet holding piece (42). The fitting protruding part (44) fits in the holder attaching groove (45). The magnet holding piece (42) is provided with a first contact part (46), a second contact part (47) and a noncontact part (48), and a magnet storing part (43)is formed with the magnet holding piece (42) which the adjacent holder arm (32) faces and a rotor core outer circumference plane (16a). In the magnet storing part (43), a rotor magnet (17) is press fitted and fixed from the shaft direction. Thus, a magnet fixing structure wherein the magnet can be fixed to the rotor core and the like at a high accuracy and low cost is provided.