A spindle unit for a machine tool for fine-machining workpieces having groove-shaped profiles, has a rotatably mounted spindle shaft (2). The spindle shaft is subdivided in the axial direction (AR), one behind the other, into a fastening portion (A) for fastening a tool (4) or a workpiece to be machined, a first bearing portion (B), a force transmission portion (C), and a second bearing portion (D). A drive unit (5) serves to drive the spindle shaft by way of force transmission onto the force transmission portion. A first and a second bearing point (13, 14) are designed to bear the spindle shaft in the first bearing portion, and a third bearing point (15) serves to mount the spindle shaft on the second bearing portion. The first and the second bearing points each have one or more hydrostatic bearings. The third bearing point has one or more hydrostatic and/or hydrodynamic bearings.