To provide an inexpensive air guide device causing less damage of a member.

A cross-sectional shape orthogonal to an axial direction of an X guide member 11 is non-circular, an angle made by neighboring faces of an outer peripheral face of the X guide member 11 is an obtuse angle, the outer peripheral face is provided with main faces 11a-11d and sub faces 11e-11h narrower than the main faces, filling members 17 are filled in portions of an X slider 12 at positions corresponding to the sub faces 11e-11h of the X guide member 11, an inner peripheral face of the X slider 12 including the filling members 17 and the outer peripheral face of the X guide member 11 facing it respectively have shapes corresponding to each other, so that a space between the X guide member 11 and the X slider 12 gets narrower to cause less air leakage from between the X guide member 11 and the X slider 12, and an acute angle part or a right angle part susceptible to damage are excluded from the X guide member 11 to cause less damage of the X guide member 11.