A seat slide device for a vehicle includes a lower rail, an upper rail movable relative to the lower rail and a lock member for restricting the relative movement of the upper and lower rails. The restriction of the relative movement can be released and the lock-released position can be retained. The seat slide device further includes a memory piece detachably engaged with the lower rail and provided in a direction separating from the lower rail and engaging therewith when a seatback is reclined forward, wherein the memory piece is moved in association with the movement of the upper rail by retaining the memory piece at the receiving portion and the shaped portion when the memory piece is separated from the lower rail and wherein the memory piece is engaged with the lower rail at the engaging portion when the memory piece is engaged with the lower rail.