An illumination system includes an alert unit connected to a control device. During work to connect the illumination equipment to the relay, the control device searches whether or not the illumination equipment is connected, through the relay; when the connection of the illumination equipment is detected, sends an inquiry on a type of the illumination equipment to the illumination equipment and acquires information on the type of the illumination equipment; when the information on the type of the illumination equipment is the same as the planned connection equipment type stored in advance, sets an identification number for the illumination equipment connected to the control device; and, when the information on the type of the illumination equipment differs from the planned connection equipment type stored in advance, causes the alert unit to generate a first alert.