A stator includes a hollow cylindrical stator core comprised of a plurality of stator core segments and an outer cylinder fitted on the radially outer surface of the stator core. The stator core has a recess formed in the radially outer surface and the recess has an engaging wall surface that extends in both the axial and radial directions of the stator core. The outer cylinder has a fastening portion for fastening the outer cylinder to the stator core. The fastening portion is formed to be partially surrounded by a plurality of first slits and a second slit. The fastening portion is bent radially inward to have a second slit-side end part thereof received in the recess of the stator core. Further, the second slit-side end part of the fastening portion has a distal end engaging with the engaging wall surface of the recess of the stator core.