A fuel injection device including a fuel injection unit and a fuel supply system supplying fuel to the fuel injection unit, the fuel injection unit 10 comprising: a plurality of fuel injection members including a first fuel injection member 40 disposed in a center of the fuel injection unit and an annular second fuel injection member 50 surrounding the first fuel injection member, each of the fuel injection members having a port 44,54 through which fuel is injected; an atomizing mechanism 60 disposed between the first fuel injection member 40 and the second fuel injection member 50, and around the second fuel injection member 50 to atomize fuel which is injected from the fuel injection members; and a mixing duct 80 surrounding the fuel injection members and the atomizing mechanism, wherein annular air passages for combustion air are formed between the first fuel injection member 40 and the annular second fuel injection member 50, and between the annular second injection member 50 and the mixing duct 80, so that fuel is atomized and mixed with the combustion air flowing through the annular air passages by means of the atomizing mechanism, each of the annular air passages having an annular air inlet at an upstream end of the annular air passage, and wherein the fuel supply system comprises: a holding-and-supplying unit 20, configured to hold the fuel injection unit and supply fuel to each of the fuel injection members of the fuel injection unit; and a connecting-and-supplying unit 30 configured to connect the plurality of fuel injection members to the holding-and-supplying unit 20; wherein fuel supply passages 23,24;31,32 are formed in the holding-and-supplying unit 20 and the connecting-and-supplying unit 30 so as to extend from the holding-and-supplying unit through the connecting-and-supplying unit to the fuel injection members, wherein portions of the fuel supply passages 31,32 formed in the connecting-and-supplying unit 30 are formed so as to overlap each other with respect to a flowing direction of combustion air; characterized in that the holding-and-supplying unit 20 is arranged at a circumferential edge of the mixing duct 80. a plurality of fuel injection members including a first fuel injection member 40 disposed in a center of the fuel injection unit and an annular second fuel injection member 50 surrounding the first fuel injection member, each of the fuel injection members having a port 44,54 through which fuel is injected; an atomizing mechanism 60 disposed between the first fuel injection member 40 and the second fuel injection member 50, and around the second fuel injection member 50 to atomize fuel which is injected from the fuel injection members; and a mixing duct 80 surrounding the fuel injection members and the atomizing mechanism, wherein annular air passages for combustion air are formed between the first fuel injection member 40 and the annular second fuel injection member 50, and between the annular second injection member 50 and the mixing duct 80, so that fuel is atomized and mixed with the combustion air flowing through the annular air passages by means of the atomizing mechanism, each of the annular air passages having an annular air inlet at an upstream end of the annular air passage, a holding-and-supplying unit 20, configured to hold the fuel injection unit and supply fuel to each of the fuel injection members of the fuel injection unit; and a connecting-and-supplying unit 30 configured to connect the plurality of fuel injection members to the holding-and-supplying unit 20; wherein fuel supply passages 23,24;31,32 are formed in the holding-and-supplying unit 20 and the connecting-and-supplying unit 30 so as to extend from the holding-and-supplying unit through the connecting-and-supplying unit to the fuel injection members, wherein portions of the fuel supply passages 31,32 formed in the connecting-and-supplying unit 30 are formed so as to overlap each other with respect to a flowing direction of combustion air; characterized in that the holding-and-supplying unit 20 is arranged at a circumferential edge of the mixing duct 80.