The invention relates to a ball screw (1) comprising a ball caster spindle (3) and a driven spindle nut (2) arranged thereon. Balls (7) are arranged in a continuously rotatable manner in at least one endless ball channel (8), said ball channel (8) comprising a load section (9) which is wound around the ball caster spindle (3) and defined by ball tracks (10, 11) of the ball caster spindle (3) and the spindle nut (2), and a load-free recycling section (12) which continuously connects the beginning and end thereof. A regreasing device (15) which is arranged on the spindle nut (2) in a rotationally fixed manner supplies lubricant to the ball channel (8) using centrifugal force.