In a linear guide device including: a rail having on either side surface thereof a track recess with a track surface formed thereon; a rail cover covering a rail upper surface of the rail; a saddle-like slider moving linearly on the rail; and a rolling member circulating through a connection path provided in the slider and adapted to roll on the track surface of the rail, the rail cover is equipped with a side edge portion having an engagement portion, an upper track surface serving as an engagement surface is provided in a lower portion of an upper side surface of the rail, the engagement surface being a slope gradually diminishing in the rail width direction downwardly from the upper side surface, and an engagement portion of the rail cover is engaged with the engagement surface, whereby it is possible to achieve an increase in the speed of the rail grinding work for allowing engagement of the rail cover covering the rail upper surface of the liner guide device.