A position detection apparatus is provided which eliminates the necessity of space to affix a scale to a track member. A track member of a motion guide apparatus is provided with a through hole into which a fastening member to fasten the track member to a base can be inserted. A carriage that is movably assembled to the track member via a rolling element is provided with magnets generating a magnetic field toward the track member. Magnetic sensors that detect a change in the magnetic fields of the magnets with the travel of the magnets relative to the track member are placed within the magnetic fields of the magnets.