A dishwasher is disclosed. The dishwasher includes a tub, a main arm and an auxiliary arm for spraying water to an object to be washed, a fixed gear unit for rotatably supporting the main arm, a rotating gear unit configured to be rotated in engagement with the fixed gear part, a link unit for allowing the auxiliary arm to perform a reciprocating rolling movement, and an auxiliary arm connection unit. The auxiliary arm connection unit includes an extension pipe, a shaft extending from the extension pipe in order to support an interior of the auxiliary arm, and a sealing member protruding from an outer circumferential surface of the extension pipe. The sealing member includes a support member provided on at least one of an upper portion of the sealing member and a lower portion of the sealing member in order to support the interior of the auxiliary arm.