Abstract: A vehicle seat lumbar support including: brackets located on both sides of a seat back frame; a fixing unit having guides for guiding an operating unit and a driver including a motor having a driving shaft, a worm fitted to the driving shaft of the motor, a worm gear rotating by the worm, and a pinion gear fitted to a shaft of the worm gear; and an operating unit driven by the driver and including a block band having base blocks having hooks formed on underside surfaces thereof, a base band for locking the hooks of the base blocks thereonto in such a manner as to be coupled to the guides on top and underside of one side thereof, and a rack gear formed on the base band in such a manner as to engage with the pinion gear fitted to the shaft of the worm gear.