PURPOSE: To form a multi-driving device in which register errors in the sheet length direction are corrected by receiving register error information between two printing units and changing the output ratio of two motors correspondingly.

CONSTITUTION: When a dislocation in the measured values of a sheet detecting device 12 in the synchronous conveyance of sheets between two printing units 2 is generated, a controller 13 measures the correction value Ikorr of a target current value Isoll based on the positional error of a sheet 9. The positive correction value Ikorr is added to one of the two printing units 2 in which the error of the sheet conveyance occurred, while the negative correction value Ikorr is added to the other printing unit 2. In this way, the sum of the current Isoll+Ikorr and Isoll-Ikorr, accordingly the driving torque of two driving motor 15 is secured to be kept constant. In this manner, by the driving apparatus, the positional error of the sheet 9 generated between the two printing units 2 can be compensated before the sheet 9 arrives at a next pressure cylinder 8.