An aroma diffusion system comprising: an aroma diffusion unit having a plurality of aroma patterns to be diffused, the aroma diffusion unit being configured to diffuse an aroma corresponding to the aroma pattern into a target space; an acquisition unit configured to acquire person information on at least one of an activity and a mood of a person in the target space; a measurement unit (14, 16) configured to measure a temperature and a humidity of the target space; a storage unit including, as information storage regions, a correspondence information database and a pattern database, the correspondence information database storing a list of a combination of the activity or the mood of the person in the target space, the temperature of the target space, and the humidity of the target space, and the aroma pattern, the combination and the aroma pattern being associated with each other in the list, the pattern database storing a list of an aroma type, an aroma diffusion amount, and an aroma diffusion duration set for each of the aroma patterns; and an identification unit configured to identify at least one of the activity and the mood of the person in the target space, based on the person information acquired by the acquisition unit; an aroma determination unit configured to determine the aroma pattern of the aroma diffusion unit based on the information stored in the correspondence information database, a result of the identification by the identification unit, and the temperature of the target space and the humidity of the target space; an aroma diffuser control unit configured to, when the aroma determination unit determines the aroma pattern, read, referring to the pattern database, the aroma type, the aroma diffusion amount, and the aroma diffusion duration corresponding to the aroma pattern determined by the aroma determination unit, and control the aroma diffuser to operate under the read-out conditions to diffuse an aroma corresponding to the determined aroma pattern into the target space, characterized by: a learning unit configured to learn about a change in at least one of the activity and the mood before and after the aroma diffusion unit diffuses the aroma corresponding to the aroma pattern, and rewrite at least one of the information in the correspondence information database and the information in the pattern database in accordance with the result of the learning. an aroma diffusion unit having a plurality of aroma patterns to be diffused, the aroma diffusion unit being configured to diffuse an aroma corresponding to the aroma pattern into a target space; an acquisition unit configured to acquire person information on at least one of an activity and a mood of a person in the target space; a measurement unit (14, 16) configured to measure a temperature and a humidity of the target space; a storage unit including, as information storage regions, a correspondence information database and a pattern database, the correspondence information database storing a list of a combination of the activity or the mood of the person in the target space, the temperature of the target space, and the humidity of the target space, and the aroma pattern, the combination and the aroma pattern being associated with each other in the list, the pattern database storing a list of an aroma type, an aroma diffusion amount, and an aroma diffusion duration set for each of the aroma patterns; and the correspondence information database storing a list of a combination of the activity or the mood of the person in the target space, the temperature of the target space, and the humidity of the target space, and the aroma pattern, the combination and the aroma pattern being associated with each other in the list, the pattern database storing a list of an aroma type, an aroma diffusion amount, and an aroma diffusion duration set for each of the aroma patterns; an identification unit configured to identify at least one of the activity and the mood of the person in the target space, based on the person information acquired by the acquisition unit; an aroma determination unit configured to determine the aroma pattern of the aroma diffusion unit based on the information stored in the correspondence information database, a result of the identification by the identification unit, and the temperature of the target space and the humidity of the target space; an aroma diffuser control unit configured to, when the aroma determination unit determines the aroma pattern, read, referring to the pattern database, the aroma type, the aroma diffusion amount, and the aroma diffusion duration corresponding to the aroma pattern determined by the aroma determination unit, and control the aroma diffuser to operate under the read-out conditions to diffuse an aroma corresponding to the determined aroma pattern into the target space, characterized by: a learning unit configured to learn about a change in at least one of the activity and the mood before and after the aroma diffusion unit diffuses the aroma corresponding to the aroma pattern, and rewrite at least one of the information in the correspondence information database and the information in the pattern database in accordance with the result of the learning.