A diffuser device (1) for volatile substances comprises a motor unit (2) and a refill unit (3) which can be assembled with each other. The motor unit (2) comprises a fan (6) for sucking in air comprising a body (60) and an electric motor (M1) which drives a plurality of blades (62) in rotation, electrical power supply means (4, 5) for the motor (M1) and a structure (20, 21) to support the fan (6) and the power supply means (4, 5). The refill unit comprises a refill of volatile substances (9), air filtering means (90) and a support structure (30) for the refill (9) and the filtering means (90). The filtering means (90) are situated upstream of the fan (6) to filter all the air sucked in by the fan (6). A laminar air flow generated in the fan body (60) strikes the refill (90) to favour diffusion of the volatile substances.