A pitch conversion device and pitch conversion method is directed to convert the pit of a plurality of partition members (90) arranged parallel to each other along The X-direction and include a plurality of entry members (11) arranged parallel to each other in The X-direction and configured to enter between neighboring partition members (90), and a pushing member (31) to push the plurality of entry members (11) in turn and allow them to enter neighboring partition members (90) associated while moving in the X direction. The entry members (11) are biased in a exiting direction from between the neighboring partition members (90).