End-plates for linear motion sliders and linear motion sliders for use with the end-plates, particularly an end-plate for linear motion sliders and a linear motion slider for use with the end-plate, in which first and second support portions, which contact and support the outer surfaces of balls, are provided in the circumferential inner surface of the end-plate, and a space is defined between the outer surfaces of the balls and a junction surface between the first and second support portions. Therefore, the stiffness of the end-plate is increased, and the balls can stably circulate in a slider, thus reducing noise and vibration. Furthermore, the space serves to keep lubricant therein, whereby the balls can more efficiently circulate in the slider.