SEAT SLIDE DEVICE FOR VEHICLE

PROBLEM TO BE SOLVED: To provide a seat slide device for a vehicle capable of detachably engaging engaging projection parts of a lock lever with an engaged part more smoothly without requiring stringent tolerance control.SOLUTION: A lock mechanism has a lock lever 31 which has a rotation shaft M crossing both sidewall parts 15 and is supported by an upper rail 6. In addition, engaging projection parts 36 projecting in the width direction are provided at one end of the lock lever 31. Specifically, the engaging projection parts 36 are provided at only one side in the width direction in the lock lever 31. Further, insertion holes 37 to which the engaging projection parts 36 are vertically movably inserted are provided at sidewall parts 15 (15B) crossing the engaging projection parts 36. Then, a plurality of engaging holes 38 having an upper opening part with which the engaging projection parts 36 can be detachably engaged based on the rotation of the lock lever 31 are provided on a lower rail 5.