<p>Locking device of a longitudinal adjusting unit of a vehicle seat comprises a locking strip (28) having periodically arranged locking openings (30) and locking pins assigned to a base rail (22) of the longitudinal adjusting unit; and a barrier unit assigned to a seat rail (20) of the longitudinal adjusting unit and having at least two plunger pins (40) which interact with the locking openings. The plunger pins are arranged in a guiding part (36) which has a hole for each pin. At least one of the plunger pins has a groove region (50) located close to a lower end of the opening when the plunger pin is locked in the one of the locking openings. Preferred Features: The groove region has at least one single groove, preferably several grooves (56). The groove region has at least one edge on the free end of the plunger pins close to the groove edge. The plunger pins have a free end and an operational end.</p>
