A fixing structure for a permanent magnet includes: a cylindrical housing; a permanent magnet housed inside the housing; and an adhesive layer formed in a gap G between the housing and the permanent magnet and having an adhesive for fixing the permanent magnet to the housing. The adhesive layer is formed such that a filling rate of the adhesive is higher in the gap at another axial end of the permanent magnet than at one axial end of the permanent magnet. The permanent magnet is configured such that a density at said other axial end is higher than the density at said one axial end.