A linear motion guide device includes a slider slidably attached onto the guide rail, a ball bearing device disposed between the slider and the guide rail, and a lubricating device having a housing slidably attached onto the guide rail for receiving and for supplying a lubricant to lubricate the ball bearing device. A lubricant-conveying member is disposed in the housing and has an upper segment and one or more lower segments and one or more middle segments coupled between the upper segment and the lower segments for absorbing the lubricant even when the lubricant is below a lower level and even when the housing is tilted or turned up side down relative to the slider and the guide rail.