A dishwasher comprising: a tub having therein a space for receiving objects to be washed; a main arm rotatably provided in the tub for spraying wash water to the objects; an auxiliary arm rotatably provided at the main arm for spraying wash water to the objects; a stationary gear unit fixed in the tub for rotatably supporting the main arm, the stationary gear unit being provided at an outer circumferential surface thereof with gear teeth; an eccentric rotation unit (500a, 500b, 500c) rotatably mounted at the main arm so as to be engaged with the stationary gear unit, the eccentric rotation unit (500a, 500b, 500c) being configured to be rotated by rotation of the main arm for transferring rotational force within a rotational resistance limit of the auxiliary arm; and a link member movably supported by the main arm for transferring the rotational force of the eccentric rotation unit (500a, 500b, 500c) to the auxiliary arm to rotate the auxiliary arm; wherein the eccentric rotation unit (500a, 500b, 500c) comprises: an eccentric part (520a, 520b, 520c) rotatably coupled to the main arm; and an elastic gear (510a, 510b, 510c) coupled to the main arm coaxially with the eccentric part (520a, 520b, 520c) for transferring rotational force of the stationary gear unit to the eccentric part (520a, 520b, 520c) within the rotational resistance limit of the auxiliary arm, characterized in that the eccentric part (520a, 520b, 520c) comprises a rotary plate (521a, 521b) held by the elastic gear (510a, 510b, 510c), a shaft rotatably coupled to the main arm, an eccentric protrusion (527a, 527b, 527c) disposed eccentrically with respect to the shaft, and a catching projection (525a, 525b, 525c) for receiving rotational force from the elastic gear (510a, 510b, 510c), and wherein the elastic gear (510a, 510b, 510c) comprises a rotary boss (517a, 517b, 517c) coupled to the main arm coaxially with the shaft and an elastic part provided at an inner circumferential surface of the elastic gear (510a, 510b, 510c) and held by the catching projection (525a, 525b, 525c) with a predetermined elastic force for transferring rotational force to the eccentric part (520a, 520b, 520c). a tub having therein a space for receiving objects to be washed; a main arm rotatably provided in the tub for spraying wash water to the objects; an auxiliary arm rotatably provided at the main arm for spraying wash water to the objects; a stationary gear unit fixed in the tub for rotatably supporting the main arm, the stationary gear unit being provided at an outer circumferential surface thereof with gear teeth; an eccentric rotation unit (500a, 500b, 500c) rotatably mounted at the main arm so as to be engaged with the stationary gear unit, the eccentric rotation unit (500a, 500b, 500c) being configured to be rotated by rotation of the main arm for transferring rotational force within a rotational resistance limit of the auxiliary arm; and a link member movably supported by the main arm for transferring the rotational force of the eccentric rotation unit (500a, 500b, 500c) to the auxiliary arm to rotate the auxiliary arm; wherein the eccentric rotation unit (500a, 500b, 500c) comprises: an eccentric part (520a, 520b, 520c) rotatably coupled to the main arm; and an elastic gear (510a, 510b, 510c) coupled to the main arm coaxially with the eccentric part (520a, 520b, 520c) for transferring rotational force of the stationary gear unit to the eccentric part (520a, 520b, 520c) within the rotational resistance limit of the auxiliary arm, an eccentric part (520a, 520b, 520c) rotatably coupled to the main arm; and an elastic gear (510a, 510b, 510c) coupled to the main arm coaxially with the eccentric part (520a, 520b, 520c) for transferring rotational force of the stationary gear unit to the eccentric part (520a, 520b, 520c) within the rotational resistance limit of the auxiliary arm, characterized in that the eccentric part (520a, 520b, 520c) comprises a rotary plate (521a, 521b) held by the elastic gear (510a, 510b, 510c), a shaft rotatably coupled to the main arm, an eccentric protrusion (527a, 527b, 527c) disposed eccentrically with respect to the shaft, and a catching projection (525a, 525b, 525c) for receiving rotational force from the elastic gear (510a, 510b, 510c), and wherein the elastic gear (510a, 510b, 510c) comprises a rotary boss (517a, 517b, 517c) coupled to the main arm coaxially with the shaft and an elastic part provided at an inner circumferential surface of the elastic gear (510a, 510b, 510c) and held by the catching projection (525a, 525b, 525c) with a predetermined elastic force for transferring rotational force to the eccentric part (520a, 520b, 520c).