This paper deals with the vertical striped pattern formed on the ground surface by high-reciprocation grinding. The high-reciprocation grinding is characterized by the high-speed motion of work table reciprocation, and has become of major interest lately as a new way of high quality and efficiency machining in the production of the punch for the IC lead frames. On the ground surface, the striped pattern appears in the direction perpendicular to the direction of work table reciprocation, and the pattern is clearly noticed as the ground surface becomes smoother like a mirror. Although the roughness of the striped pattern is not so large, it becomes the problem that the pattern can be observed visually. In this paper, the formation mechanism of the striped pattern is investigated through a computer simulation and grinding tests. As a result, it becomes clear that the striped pattern appears on the ground surface due to the interaction between the grinding marks generated by the unbalanced wheel. Furthermore, the striped pattern was easily formed after grinding with faster work table reciprocation or lower cross feed speed.