The problem in improving the positioning precision of a permanent magnet linear synchronous motor (LSM) is the large detent force caused by the permanent magnet. The detent force is thought to arise from the difference of the position of a permanent magnet end and a tooth position. If one detent force is independent from the other, we can reduce the total detent force of the permanent magnet linear synchronous motor by the arrangement of a permanent magnet end and a tooth. This paper presents are improvement of the arrangement of the permanent magnet end of a linear synchronous motor in order to reduce the detent force by using numerical analysis.