In this paper, the driving force of a linear-guideway type recirculating ball bearing (linear bearing) is measured and explained as the first step toward an understanding of sticking, which is the significant increase in driving force required to move a linear bearing under back-and-forth operation with a short stroke length. First, the driving force required for operation of a test bearing (which is a linear-guideway type recirculating ball bearing with load balls) and acceleration of a moving body (which consists of a carriage of the test bearing, an arm, and weight) were measured. The measurements showed that the sticking occurred when the test bearing, under a relatively higher rolling moment load, was driven in an offset position for a certain period. Next, the driving force of a test bearing with alternating load balls and spacer balls was measured, and it was clear that the cause of the sticking was the sliding friction between rolling balls. Finally, the ball locations in the load zone of the test bearing with load balls were observed in operation, and the occurrence process of the sticking is explained.