To provide a folding machine saw device in a rotary press, comprising paper retainers in a sawing shell for maintaining good repulsion and restoration for a long period while gaining a great deforming stroke in the pressing direction.

The folding machine saw device in a rotary press is provided in the saw shell 20. It comprises a saw blade 11 and the pair of paper retainers 12, 12' arranged on both sides of the saw blade. Continuous printing paper W guided between the saw shell and a folding shell 30 approaching the saw shell in opposition thereto is retained on the peripheral face of the folding shell by the pair of paper retainers, and the continuous printing paper in the middle retained by the pair of paper retainers is cut by the saw blade. The paper retainer is formed of a soft elastic material, where at-least-one-line longitudinal grooves 60, 60' are formed in the end faces on the cutting edge sides of the paper retainers to form at-least-two-line protruded blocks 70, 70', 71, 71'. The protruded blocks each have at least one crossing groove portion, and can be in non-continuous form in the longitudinal direction.