POWER SEAT SIDE DEVICE

PROBLEM TO BE SOLVED: To prevent lateral play while a dimensional error of a movable rail remains by forming a projection part of which tip is elastically in contact with both right and left end parts of the movable rail on both the right and left sides of an end cap, respectively. SOLUTION: A projection part 28 protruding toward both the right and left sides is integrally formed in a flange part 21 of an end cap 19. This projection part 28 has a pointed tip and is elastically in contact with a lip part 11 of a movable rail 10 in a small are. In this way, by forming the projection part 28 of which tip is elastically in contact with the lip part 11 of the movable rail 10 on both the right and left sides, respectively, in the flange part 21 of the end cap 19, it is possible to prevent the occurrence of lateral play of the movable rail 10, even if a dimensional error at the time of manufacture remains between the movable rail 10 and a fixed rail 1. Furthermore, since the tip of the projection part 28 comes in contact with the lip part 11 of the movable rail 10 elastically in a small area, slide resistance of the movable rail 10 does not increase greatly.