A longitudinal adjuster (3) for a vehicle seat (1) includes at least one rail pair (7), including a lower rail (9) and an upper rail (11), which can be moved longitudinally in relation to the lower rail (9). At least one locking unit (13) locks the upper rail (11). At least one actuating element (5) releases the locking of the upper rail (11). The locking unit (13) includes at least one locking element (15) and at least one spring element (17), which are operatively engaged with each other. The spring element (17) is interlockingly and frictionally connected to the upper rail (11) by an insertion locking connection (S). The spring element (17) applies a preloading force to the actuating element (5) and to the locking element (15). A vehicle seat (1) is also provided with at least one such longitudinal adjuster (3).