A retainer to be installed in a linear motion guide unit is disclosed which composed of embracing parts to hold a roller on diametrically opposite sides thereof, and connecting flanges joining the embracing parts together with one another. The embracing parts to hold the roller between them are each made with a first lip raised above any one side thereof, and a second lip raised above another side thereof. The first and second lips raised in opposite direction are placed in an offset or staggered relation with one another in lengthwise direction of the embracing part or in axial direction of the roller so as to be tough to suffer any distortion and/or damage on molding operation. The retainer can sustain ample lubricant near the lips. The embracing parts come into rolling-contact with the rolling surface of the roller while the connecting flanges come into sliding contact with axially opposite ends of the roller.