An adjustable multiple-ring polarizing neutral-density filter assembly with an elastic engaging member for axial ring securement includes a fixedly connecting ring and a first pivotally connecting ring. The fixedly connecting ring is mounted with a polarizing lens and has a first end threadedly connectable to a camera lens and an opposite second end axially provided with a receiving groove. The elastic engaging member is mounted in the receiving groove and has a free end extending out of or forced into the receiving groove. The first pivotally connecting ring is mounted with another polarizing lens and has one end pivotally connected to the second end of the fixedly connecting ring and circumferentially provided with an engaging portion. The free end of the elastic engaging member can press against the bottom wall of any of the engaging recesses in the engaging portion to maintain the corresponding light-reducing effect while being shaken.