A side lay position control apparatus for a sheet-fed printing press, includes a switch (11,21) for setting a distance from a reference point (41) of the sheet-fed printing press (31) to a side lay and a fine adjustment length with reference to the distance, a CPU (1) for calculating an actual distance from the reference point (41) to the side lay in accordance with the distance from the reference point (41) to the side lay unit (36) and the fine adjustment length, and a driver (8,35) for moving the side lay unit (36) in accordance with the actual distance.