PURPOSE: To obtain a device which is capable of adjusting degree of variation of a cutting blade's rotating speed as required without requiring extra cost in such a manner as to convert equal speed rotation to non-equal speed rotation by using a special motion-conveying mechanism and convey the motion to the cutting blade.

CONSTITUTION: A shaft 44 is installed through 2 pairs of non-circular pinions 48 and 50 in a free-to-rotate position and its driving is linked to a cutting blade supporting shaft 52, one end of which is provided with a cutting blade 12. A relative angle θ of the pairs of pinions 48 and 50 is to be freely adjustable. As compared with the case in which a pair of non-circular pinions of the same flatness are used, variation of rotating speed of the cutting blade 12 becomes fairly different, and at the same time, it makes a large difference in variation of speed in a cap shell conveying direction at outer edge of radial direction of the cutting blade 12 in a region before and after the time when a rotating angle of a non-circular pinion 54 on input side of the pairs of pinions 48 becomes θ=0, that is, the time when radial direction outer edge of the cutting blade 12 closes most to inside bottom surface of the cap shell 4.