A lordosis support for a seat back rest, includes a support plate, tension members for holding the support plate between two frame legs of the seat back rest, the support plate having on each side at least one point of attack for a respective tension member, and an adjusting device for adjusting a tension force of the tension members by changing the distance between the two points of attack, wherein the distance between the two points of attack is adjustable and the adjusting device is configured to change this distance, wherein the support plate is a one-piece support plate, and the two points of attack are linearly moveably arranged at the one-piece support plate for translational movement.