A holding device for an air freshener includes a hanging member and a base member. The hanging member includes a rack and a belt. The rack includes two separate hooks arranged in parallel with a reinforcing beam in between. The hooks have their front ends extended downward into two columns, and bended perpendicularly forward and joined into a bottom ring. A top ring is perpendicularly welded to the columns above the bottom ring. The belt has a ring and two belt pieces, and each belt piece is extended from the ring and a buckle at an outer end of the belt piece. The base member includes a cup and an L-shaped seat with a planar element and a wall element. The planar element has a central through opening, and the cup is joined to the planar element from below and exposed by the through opening.
