An image-forming device comprising: a casing; a developing unit that is detachably mounted in the casing and formed with a first opening (171, 174), the developing unit having a developer carrying member carrying a developer; a first shutter opening and closing the first opening (171, 174); a developer cartridge that is detachably mounted in the casing, accommodates the developer, and is formed with a second opening (96, 112), the second opening (96, 112) being in alignment with the first opening (171, 174); a second shutter opening and closing the second opening (96, 112); and an alignment member that is disposed between the developing unit and the developer cartridge and is formed with a third opening (33, 34), the third opening (33, 34) being in alignment with the first opening (171, 174) and the second opening (96, 112); and a third shutter (71, 37) that is disposed in the alignment member and opens and closes the third opening (33, 34), wherein the opening and closing operations of the first shutter or the second shutter are performed in association with the opening and closing operation of the third shutter; wherein the developer carrying member is a developing roller having a shaft and the developer cartridge is disposed in the casing so as to confront the developer carrying member in the direction of the shaft of the developer carrying member; wherein the alignment member is a sidewall of a cartridge accommodating space formed in the casing for accommodating the developer cartridge, the alignment member being perpendicular to the shaft and supporting one end of the developing unit and one end of the developer cartridge. a casing; a developing unit that is detachably mounted in the casing and formed with a first opening (171, 174), the developing unit having a developer carrying member carrying a developer; a first shutter opening and closing the first opening (171, 174); a developer cartridge that is detachably mounted in the casing, accommodates the developer, and is formed with a second opening (96, 112), the second opening (96, 112) being in alignment with the first opening (171, 174); a second shutter opening and closing the second opening (96, 112); and an alignment member that is disposed between the developing unit and the developer cartridge and is formed with a third opening (33, 34), the third opening (33, 34) being in alignment with the first opening (171, 174) and the second opening (96, 112); and a third shutter (71, 37) that is disposed in the alignment member and opens and closes the third opening (33, 34), wherein the opening and closing operations of the first shutter or the second shutter are performed in association with the opening and closing operation of the third shutter; wherein the developer carrying member is a developing roller having a shaft and the developer cartridge is disposed in the casing so as to confront the developer carrying member in the direction of the shaft of the developer carrying member; wherein the alignment member is a sidewall of a cartridge accommodating space formed in the casing for accommodating the developer cartridge, the alignment member being perpendicular to the shaft and supporting one end of the developing unit and one end of the developer cartridge.