A linear motion guide device includes a slider slidably attached onto a guide rail and each having one or more longitudinal grooves for forming a ball guiding channel between the slider and the guide rail, and two end caps attached to the ends of the slider, the slider includes two end portions each having two notches communicating with the longitudinal grooves, and two plates are disposed between the slider and the end caps and each include two or more ears engaged into the notches of the slider for anchoring the plates to the slider and each ear having an inclined surface for reducing the noises that may be generated by the movement of the ball bearing device.