Spindle device

A built-in motor type spindle device comprising a housing and a spindle, wherein said spindle device further includes static pressure bearings which support the spindle so that the spindle can rotate freely relatively to the housing, two lines of magnetic field generating members which are provided on the spindle, and two pairs of coils which are provided on the housing and respectively face the magnetic field generating members and since the spindle device circumferentially disperses the which magnetic field generating members generate heat, the spindle device can prevent the spindle from being hot locally and further, since the surface area of the magnetic field generating members on the spindle are made larger, they can be cooled more effectively than one line of magnetic field generating members.