A device for adjusting the spring force pressing two axially parallel folding rollers, which comprises a shaft and two folding rollers having parallel axes and supported in swivel bearings. An abutment is spaced apart from each of the swivel bearings and mounted on the shaft. A compression spring is disposed between each of the folding rollers and an abutment. Two side walls are provided. The shaft has a thread at each of its ends. One of the ends of the shaft is threaded in a bore of one of the side walls. The other of the ends of the shaft is threaded in a threaded bore of the bushing. The bushing is disposed non-rotatably and axially displaceably in a bore of the other of the side walls, and the pitch of the threaded bore of the bushing is twice as great as the pitch of the threaded bore of said one of the side walls.