A permanent magnet motor for driving a fan is rotated while a movement of the
rotor
in a direction of thrust of a rotary shaft with a rotation of the fan is prevented
by magnetic attraction force of a permanent magnet and a stator core. A surface
magnetic flux density of the permanent magnet facing the stator core is lower at
an end portion than at a central portion of the permanent magnet in the direction
of thrust of the rotary shaft.