A pointing device includes a casing in which a track ball is rotatably received and physically engaging two substantially perpendicular rotatable axles and a biasing structure forcibly biasing the track ball toward the axles. The biasing structure includes a frame rotatably supported inside the casing by pivots and a retainer mounted to the frame. The retainer includes a plurality of pawls spaced along a circumference to form a space for rotatably receiving and retaining a sphere. A biasing element is arranged between the casing and the frame to bias the sphere to forcibly engage the track ball thereby forcing the track ball against the rotatable axles.