To provide an XY driving device and a preload control method thereof, which can estimate and adjust a preload, without arranging a sensor for measuring the preload in a divided type rolling guide.

This XY driving device sets a linearly moving mechanism having a feed screw having a rolling element as the X axis, and a linearly moving mechanism having the divided type rolling guide as the Y axis. The feed screw has a first nut and a second nut, and the first nut is integrated with or fastened to one Y axis slider or a Y axis guide rail of the divided type rolling guide, and the second nut is integrated with or fastened to the other Y axis slider or the Y axis guide rail of the divided type rolling guide.