A balloon coating method for forming a coating layer containing a water-insoluble drug on an outer surface of a balloon of a balloon catheter. The method includes moving a drive shaft relative to at least one of a hub of the balloon catheter and an interlocking member. The drive shaft is configured to rotate the balloon catheter about an axis of the balloon. The method fixing the drive shaft to the proximal end of the hub or to the opening of the interlocking member by frictional force, and applying a coating solution containing the drug to the outer surface of the balloon from a dispensing tube while gradually moving the dispensing tube in the axial direction and simultaneously rotating the drive shaft to rotate the balloon catheter around the axis of the balloon catheter.
