To reduce the weight of a linear servo motor and to expand an application range by providing a rod-like magnet guide member for linear servo motors that can retain high magnetic flux density on the outer surface of a pipe even if a bonded magnet is used and at the same time has a sufficient stiffness and can be formed in an arbitrary curved shape.

Magnet materials that are alternately magnetized to N and S poles are filled into a pipe 1 with a rib that is a rod-like magnet guide member for the linear servo motor of a type where a slider travels on the rod-like magnet guide member and is made of a thin hollow pipe where a plurality of projection ribs 2 project in the direction of an axial line on an inner-periphery surface. Preferably, the magnet material is made of a bonded magnet. Especially preferably, the magnet material is filled into the pipe having a rib by injection molding. In another preferable status, the pipe with the rib is made of an aluminum alloy or a magnesium alloy.