A linear guide device comprising: a guide rail ; a slider which moves relative to the guide rail ; and a rolling element , the guide rail including a guide rail orbital surface formed in a side surface portion of the guide rail in a longitudinal direction of the guide rail , the slider including a slider body including a slider orbital surface formed to face the guide rail orbital surface , and a pair of end caps provided at two ends of the slider body in a movement direction, wherein the slider further includes a retainer that retains the rolling element on a side of the slider orbital surface, in that the linear guide device further includes a seal member which seals a gap formed between the side surface portion of the guide rail and an inner side surface portion of the slider , the linear guide device being characterized in that the seal member includes a first seal member , and a second seal member which is larger in width than the first seal member and is fastened to a bottom surface of the slider to be directly in contact with and independently detachable from the bottom surface, as superimposed on the first seal member , the second seal member sliding in contact with the side surface portion of the guide rail and in that the first seal member is provided in an end portion of the retainer on the bottom side of the slider such that the first seal member separates from the second seal member in a height direction and the first seal member slides in contact with the side surface portion of the guide rail adjacent to the guide rail orbital surface obliquely against the surface portion. a guide rail ; a slider which moves relative to the guide rail ; and a rolling element , the guide rail including a guide rail orbital surface formed in a side surface portion of the guide rail in a longitudinal direction of the guide rail , the slider including a slider body including a slider orbital surface formed to face the guide rail orbital surface , and a pair of end caps provided at two ends of the slider body in a movement direction, wherein the slider further includes a retainer that retains the rolling element on a side of the slider orbital surface, in that the linear guide device further includes a seal member which seals a gap formed between the side surface portion of the guide rail and an inner side surface portion of the slider , the linear guide device being characterized in that the seal member includes a first seal member , and a second seal member which is larger in width than the first seal member and is fastened to a bottom surface of the slider to be directly in contact with and independently detachable from the bottom surface, as superimposed on the first seal member , the second seal member sliding in contact with the side surface portion of the guide rail and in that the first seal member is provided in an end portion of the retainer on the bottom side of the slider such that the first seal member separates from the second seal member in a height direction and the first seal member slides in contact with the side surface portion of the guide rail adjacent to the guide rail orbital surface obliquely against the surface portion. <EOS>