Disclosed is a linear guide device in which a rate of change expressed as nullDmaxnullDminnull, becomes extremely small where Dmax and Dmin are respectively a local maximum and a local minimum of D, expressed as (dx2nulldx1)/dx, which is produced when a steel ball B moves a distance corresponding to a rolling element-to-rolling element span, dx1 is a minute movement quantity of a steel ball B when it moves from one space defined between rolling element rolling grooves 3 and 31 of an element endless circulating raceway 7, to one of curved element circulating R parts 6, and dx2 is a minute movement quantity of another steel ball B when it moves from the other curved element circulating R part 6 to the space while the former steel ball is moved by the minute movement quantity dx1.