A linear guide apparatus has a guide rail including rolling element rolling grooves formed in the side surfaces thereof so as to extend in the axial direction thereof; a slider including rolling element rolling grooves respectively opposed to the rolling element rolling grooves of the guide rail and mounted on the guide rail so as to be movable in the axial direction with respect to the guide rail; and, a plurality of rolling elements rollably interposed between the rolling element rolling grooves of the guide rail and the rolling element rolling grooves of the slider, wherein each of the portions, where the groove surfaces of the rolling element rolling grooves of either the guide rail or the slider and the outer surfaces thereof cross each other, is formed as a curved surface, whereby the groove surface and the outer surface are allowed to continue smoothly with each other.