Rigidity and precision of a motion guidance apparatus are increased by improving track rail shape. A track rail has at least two rolling member rolling grooves (RMRGs) on the upper surface and at least one RMRG on each side surface, the RMRGs extending in the longitudinal direction. When the RMRGs are taken along a cross-sectional plane perpendicular to the longitudinal direction of the track rail, and two imaginary lines extending vertically downward are drawn from ends of the respective grooves located on the outer sides among upper surface RMRGs, all the side surface RMRG are positioned in the rail but outside the corresponding one of the two imaginary lines, and at least portions of the upper surface and the side surfaces of the track rail, on which the RMRGs are formed, the portions being in the vicinity of the respective RMRGs, are formed with an inclination angle.