shape and a mounting substrate 13 having the information storage unit 11 thereon is disposed in a rectangular opening 12 a provided at the center of the main substrate 12 with this configuration it is easy to replace the information storage unit 11 storing the information about the rank further there is an advantage of simplifying a manufacturing process of the light emitting device 1 in addition the information storage unit 11 may be configured with a plurality of resistive elements for example it is possible to identify four ranks by using at least one of the resistive element of 500 q and the resistive element of 1 kq alternatively as shown in fig3 the information storage unit 11 may be constituted by a plurality of resistive elements rj four resistive elements r 1 r 2 r 3 and r 4 in the illustrated example and four switch elements sj to separately switch on and off the conduction of each of resistive elements rj j 1 2 3 4 a desired number of ranks can be identified by appropriately combining a plurality of resistive elements each having a specific resistance value in the first embodiment the adjusting unit 21 of the lighting unit 2 is connected to the information storage unit 11 of the light emitting device 1 via the dedicated terminal block 3 d in this embodiment as shown in fig4 a resistive element.