To provide a mill drive coupling which is easily attached and detached in changing a stand and with which the generation of vibration is prevented.

This coupling is a coupling 6 for connecting the drive shaft 4A on the housing side of a roll driving shaft of a rolling mill with the drive shaft 5A on the stand side and consists of a 1st boss 20 which is attached to the drive shaft 4A on the housing side, 2nd boss 30 which is attached to the drive shaft 5A on the stand side and a torque tube 40 whose both ends are joined to the 1st and 2nd bosses 20, 30 with diaphragms 41. A 1st tapered part 32 having a larger diameter is formed on the inner side of the spline formed part of the drive shaft on the housing side, a 2nd tapered part 33 having a smaller diameter is formed at the tip, a 1st tapered hole 24 having a larger diameter is formed on the inner side of the 1st boss 20, a 2nd tapered hole 27 having a smaller diameter is formed at the tip and taper fitting is executed in two places.