A metallic flat plate base of a metallic component of a ball linear guide includes a pair of plate portions integrally connected with each other through a first flat plate portion and being formed with dovetail grooves which constitute loaded ball grooves. A first synthetic resin component is disposed so as to cover the flat plate, the first synthetic resin component having one sides which connect to a third flat plate portion to form slits, also having a pair of unloaded ball holes, and further having grooves for forming direction changing U-shaped passages which connect the loaded ball grooves and the unloaded ball holes. A pair of second synthetic resin components is mounted on the first synthetic resin component and closes the unloaded ball holes and the direction changing U-shaped passages, the pair of second synthetic resin components having other sides for forming the slits.