In an exchangeable cylinder type rotary press driven by a prime mover, it is made possible to make a print of any top-bottom length as desired, independently of a gear train that transmits power from the prime mover to an exchange cylinder unit.
To this end, the peripheral length of each of the rotary cylinders 34 - 36 in the exchange cylinder unit 28 is set at a length according to a top-bottom length of a print to be made, a profile-shifted gear is used as at least one of driven gears 37 - 39 which are provided for the rotary cylinders, respectively, and have an identical number of teeth so that the driven gears can be engaged with one another while positioning the rotary cylinders in rotational contact with one another, the printing unit 25 is provided in the exchange cylinder unit with a driving gear 30 adapted to be disengageably in engagement with one of the driven gears for driving the exchangeable cylinders, the driving gear being provided independently of the rotary printing paper feed means; and a motor 32 whose rotation is controllable is coupled to the driving gear.