An illumination system includes: a seat in a mobile body; a table to be positioned in front of a passenger when the passenger is seated on the seat; a first light source which illuminates the table; and a second light source which illuminates a region closer to the passenger than to the table. When a distance from the first light source to the table is equal to a distance from the second light source to a virtual irradiated surface, an illuminance on the table irradiated by the first light source is lower than an illuminance on the virtual irradiated surface irradiated by the second light source.