A cartridge set (10, 110) for manufacturing a dual-chamber syringe (1, 101), the cartridge set comprising: a plurality of cartridges (2, 102), each of which extends in an up-and-down direction, forms a cylindrical shape having an outer peripheral surface, and has annular ribs (2c, 2d) protruding radially outward from opening end portions thereof that correspond to both ends of the outer peripheral surface; characterized by further comprising: a plurality of holders (11, 111), each of which has flexibility, has an upper end externally fitted to the outer peripheral surface of each of the cartridges, is gradually increased in diameter as it goes downward, and has a lower end face whose outer diameter is greater than the outer diameter of the outer peripheral surface of the cartridge; a supporting plate (20, 120) that forms a plate shape that extends in a horizontal direction, has a plurality of through-holes (21, 121), each of which has an inner diameter greater than the outer diameter of the outer peripheral surface of the cartridge and has each of the plurality of cartridges inserted therethrough in the up-and-down direction, and has a top face on which the lower end faces of the plurality of holders are placed in a state where the plurality of cartridges are each inserted through the plurality of through-holes in the up-and-down direction; a storage box that forms a box shape that opens upward, stores the supporting plate therein in a state where the supporting plate supports the plurality of cartridges via the plurality of holders, and has a supporting portion which supports an outer edge of the supporting plate; and a lid member that blocks an upper end opening of the storage box. a plurality of cartridges (2, 102), each of which extends in an up-and-down direction, forms a cylindrical shape having an outer peripheral surface, and has annular ribs (2c, 2d) protruding radially outward from opening end portions thereof that correspond to both ends of the outer peripheral surface; characterized by further comprising: a plurality of holders (11, 111), each of which has flexibility, has an upper end externally fitted to the outer peripheral surface of each of the cartridges, is gradually increased in diameter as it goes downward, and has a lower end face whose outer diameter is greater than the outer diameter of the outer peripheral surface of the cartridge; a supporting plate (20, 120) that forms a plate shape that extends in a horizontal direction, has a plurality of through-holes (21, 121), each of which has an inner diameter greater than the outer diameter of the outer peripheral surface of the cartridge and has each of the plurality of cartridges inserted therethrough in the up-and-down direction, and has a top face on which the lower end faces of the plurality of holders are placed in a state where the plurality of cartridges are each inserted through the plurality of through-holes in the up-and-down direction; a storage box that forms a box shape that opens upward, stores the supporting plate therein in a state where the supporting plate supports the plurality of cartridges via the plurality of holders, and has a supporting portion which supports an outer edge of the supporting plate; and a lid member that blocks an upper end opening of the storage box.