Seat depth adjuster for a vehicle seat, comprising - a base plate which is connectable to a seat structure of the vehicle seat and which comprises a latching unit, - a carrier plate which is arranged above the base plate and which is displaceable relative to the base plate, - a locking unit which is releasably latched in the latching unit, and - a drive unit which acts on the carrier plate in the direction of displacement, wherein the carrier plate is fixed relative to the base plate in a latched position of the locking unit and is displaceable between a retracted position and an extended position in a released position of the locking unit and the drive unit causes a displacement of the carrier plate into the extended position, in the released position of the locking unit, and wherein the latching unit comprises latching receivers (8.1) which are offset in the direction of displacement and the locking unit comprises an unlocking lever with at least one locking tooth (5.1) which engages in one of the latching receivers (8.1) in a latched manner in the latched position, characterized in that the latching unit is arranged on the upper face (2.5) of the base plate facing the carrier plate, the latching receivers (8.1) are open upwardly and the at least one locking tooth (5.1) is oriented downwardly, wherein the at least one locking tooth (5.1) is arranged on the unlocking lever such that a free end of the at least one locking tooth (5.1) is arranged below the other opposing end region of the locking tooth (5.1), by which the locking tooth (5.1) is arranged or configured on the unlocking lever, and wherein the at least one locking tooth (5.1) for unlocking is movable upwardly out of the respective latching receiver (8.1) and for locking is movable downwardly into the respective latching receiver (8.1). - a base plate which is connectable to a seat structure of the vehicle seat and which comprises a latching unit, - a carrier plate which is arranged above the base plate and which is displaceable relative to the base plate, - a locking unit which is releasably latched in the latching unit, and - a drive unit which acts on the carrier plate in the direction of displacement, wherein the carrier plate is fixed relative to the base plate in a latched position of the locking unit and is displaceable between a retracted position and an extended position in a released position of the locking unit and the drive unit causes a displacement of the carrier plate into the extended position, in the released position of the locking unit, and wherein the latching unit comprises latching receivers (8.1) which are offset in the direction of displacement and the locking unit comprises an unlocking lever with at least one locking tooth (5.1) which engages in one of the latching receivers (8.1) in a latched manner in the latched position, characterized in that the latching unit is arranged on the upper face (2.5) of the base plate facing the carrier plate, the latching receivers (8.1) are open upwardly and the at least one locking tooth (5.1) is oriented downwardly, wherein the at least one locking tooth (5.1) is arranged on the unlocking lever such that a free end of the at least one locking tooth (5.1) is arranged below the other opposing end region of the locking tooth (5.1), by which the locking tooth (5.1) is arranged or configured on the unlocking lever, and wherein the at least one locking tooth (5.1) for unlocking is movable upwardly out of the respective latching receiver (8.1) and for locking is movable downwardly into the respective latching receiver (8.1).