A motor has a plurality of permanent magnet pieces aligned is such a manner as to surround an armature core and a magnetic-flux guide ring disposed between the permanent magnet pieces and the armature core for introducing a magnetic flux from the permanent magnet pieces to the armature core. The magnetic-flux guide ring has a confronting portion confronting each of the magnet pieces, an aperture formed in the confronting portion, and a connecting portion connecting adjacent two confronting portions. The aperture is formed in such a manner as to confront a boundary of adjacent magnet pieces.