The present invention provides a light-weight spacer for a slitting machine for maintaining the width between slitting knives. The light-weight spacer comprises: a spacer body having a ring structure integrally formed of metal; an inner surface positioned on the inner side of the ring structure and extending along the central axis of the ring structure; an outer surface positioned on the outer side of the ring structure and extending along the central axis of the ring structure; a first side surface extending between the inner surface and the outer surface and being perpendicular thereto; a second side surface opposite to the first side surface and extending between the inner surface and the outer surface; a first plurality of perforations provided on the first side; and a second plurality of perforations provided on the second side.