PURPOSE: To dispense with a bracket for supporting an operating lever having a lockup part and improve easiness for assembling, etc., by providing an upper rail with a pair of portions extending downwards from the top of the rail and facing each other and by causing the portions to support the operating lever.

CONSTITUTION: An upper rail 1 slidable on a lower rail 6 secured on the body of a vehicle is provided with a pair of portions 2a, 2b extending downwards from the top of the upper rail and facing each other. A through hole 2e is provided between the portions 2a, 2b. An operating lever 3 has a pair of bent portions 3b, 3c located at the tip of the lever and facing each other and has a lockup portion 3a between the bent portions so that the lockup portion is fitted to the lockup hole 6a of the lower rail 6. The lever 3 is rotatably supported at the lockup portion 3a by a shaft 4 extending through holes 3f, 2c. A helical spring 5 is provided around the shaft 4 to urge the operating lever 3 in such a direction as to fit to the lockup portion 3a in the lockup hole 6a of the lower rail 6.