The present invention relates to a fragrance (25) diffuser (20) characterised in that it comprises a first bottle (5) that can contain the fragrance and, mounted on said first bottle (5), a diffusion system (1) on which a cap or a second bottle (4) is mounted, said diffusion system (1) comprising: two pourer-stoppers (8, 9) mounted head-to-tail and each having a flow tube (8a, 9a); a plate (2) of a porous material mounted between the two pourer-stoppers (8, 9); and an outer ring (3) provided, opposite the plate of porous material (2), with at least one opening (11) for diffusing the fragrance (25), each pourer-stopper (8, 9) also including at least one flow hole (8d, 9d) enabling the fragrance (25) to pass from the bottle (4, 5) to the plate of porous material (2).