A side seal for a linear guide apparatus including a guide rail, a slider, and a plurality of rolling elements includes seal members formed of different materials, a holder plate and covers. Both seal members have recesses formed in a first face of a base and fitted with a protrusion of the holder plate. Both seal members have respective lips directed in opposite directions separated from each other. A tip of the lip of the first seal member is formed to have a shape in plane contact with the face of the guide rail. A tip of the lip of the second seal member is formed to have a shape in line contact with the face of the guide rail.