PURPOSE: To shorten a stopping time when printing is switched by simply replacing a plate cylinder receiving carriage in a printing element in a rotary press.

CONSTITUTION: A plate cylinder receiving carriage B1 used to next print is waited at left sides of printing elements 1, 2 and 3 of a rotary press charged with a plate cylinder receiving carriage A1. To replace the carriage A1 with the carriage B1, they are all simultaneously moved in one f of advancing directions. The carriage A1 becoming useless is output to right sides of the elements 1, 2, and 3, and delivered. In the case of next replacing, the carriage to be used for next printing is waited at the right sides of the elements 1, 2 and 3. This time, the entirety is moved in opposite direction to the one f. The carriage becoming useless is discharged to left sides of the elements 1, 2 and 3.