A dishwasher comprising: a tub that is forming a washing chamber in which a washing target is accommodated and opened frontward of the washing chamber; a door that is provided in the opened frontward of the tub and opens and closes the washing chamber; a sump that is disposed below the tub and stores washing water; at least one spray nozzle (20, 22, 24) for spraying the washing water stored in the sump into a space inside the tub; a heater that heats a part of the washing water stored in the sump and generates steam; a steam nozzle that is disposed in a circumferential surface of the door or the tub and supplies the steam generated by the heater to the washing chamber; a first rack that is disposed in the washing chamber, and in which the washing target washed by the washing water sprayed from the spray nozzle (20, 22, 24) is placed; and a second rack that is disposed in the washing chamber, and in which the washing target washed by the steam supplied from the steam nozzle is placed, wherein the second rack is disposed in a position where the steam discharged from the steam nozzle is supplied to the inside of the second rack through one side surface among a lower surface or a circumferential surface of the second rack, characterised in that the first rack further comprises an upper rack disposed in an upper portion of the washing chamber, and a lower rack disposed below the upper rack inside the washing chamber, wherein the second rack is detachably disposed in an inner front side of the lower rack, wherein the second rack comprises: an outer wall frame that forms a circumferential surface and a lower surface of the second rack and is formed in a lattice shape; and a support frame for supporting the washing target placed in a space formed by the outer wall frame, wherein the steam nozzle is disposed below the second rack and sprays steam toward the lower surface of the second rack in which the support frame is disposed. a tub that is forming a washing chamber in which a washing target is accommodated and opened frontward of the washing chamber; a door that is provided in the opened frontward of the tub and opens and closes the washing chamber; a sump that is disposed below the tub and stores washing water; at least one spray nozzle (20, 22, 24) for spraying the washing water stored in the sump into a space inside the tub; a heater that heats a part of the washing water stored in the sump and generates steam; a steam nozzle that is disposed in a circumferential surface of the door or the tub and supplies the steam generated by the heater to the washing chamber; a first rack that is disposed in the washing chamber, and in which the washing target washed by the washing water sprayed from the spray nozzle (20, 22, 24) is placed; and a second rack that is disposed in the washing chamber, and in which the washing target washed by the steam supplied from the steam nozzle is placed, wherein the second rack is disposed in a position where the steam discharged from the steam nozzle is supplied to the inside of the second rack through one side surface among a lower surface or a circumferential surface of the second rack, characterised in that the first rack further comprises an upper rack disposed in an upper portion of the washing chamber, and a lower rack disposed below the upper rack inside the washing chamber, wherein the second rack is detachably disposed in an inner front side of the lower rack, wherein the second rack comprises: an outer wall frame that forms a circumferential surface and a lower surface of the second rack and is formed in a lattice shape; and a support frame for supporting the washing target placed in a space formed by the outer wall frame, wherein the steam nozzle is disposed below the second rack and sprays steam toward the lower surface of the second rack in which the support frame is disposed. an outer wall frame that forms a circumferential surface and a lower surface of the second rack and is formed in a lattice shape; and a support frame for supporting the washing target placed in a space formed by the outer wall frame, wherein the steam nozzle is disposed below the second rack and sprays steam toward the lower surface of the second rack in which the support frame is disposed.