A motion guide device is provided, which is able to not only lubricate rolling-element rolling surfaces with the use of a technique totally different from conventional lubricating techniques but also maintain a lubricating capability over a long period of time. The motion guide device for use in the vacuum environment a track member (1) having a rolling-element rolling part (1a), a moving member (2) having a rolling-element circulation passage containing a loaded rolling-element rolling part (2a) facing the rolling-element rolling part (1a) and being movable relatively to the track member (2), a plurality of rolling elements (3) placed in along the rolling-element circulation passage, and a lubricant storing member storing lubricant, which member is attached to the moving member (2) without contacting the track member (1). The lubricant storing member is exposed in a space formed between the track member (1) and the moving member. The vaporized lubricant reaches the rolling-element rolling part (1a), loaded rolling-element rolling part (2a), and rolling elements (3), so that these parts and elements can be lubricated,