A dishwasher comprising: a tub providing a washing space; a door provided on a front of the tub for opening or closing the washing space; a sump provided under the tub for storing wash water; a rack provided so as to be pulled from the tub for accommodating an object to be washed; a spray arm for spraying wash water to the object to be washed; a water guide including a supply flow-path for communicating with the sump, the supply flow-path being provided inside the tub for providing a flow-path for movement of the wash water from an inside of the sump, and a supply port formed in one surface of the supply flow-path for supplying the wash water; a supply unit including a support body provided with a communication hole for communicating with the supply port in order to receive the wash water, a connection pipe extending from the support body for transferring the wash water to the spray arm, and an spray arm coupler provided on an end of the connection pipe so as to be coupled to the spray arm; and a connection member including a coupling body having one surface coupled to the water guide and a remaining surface coupled to the support body, and a through-hole formed in the coupling body so as to communicate with the supply port, wherein the supply unit further includes at least one insertion portion protruding rearward from opposite side surfaces of the support body, and wherein the connection member includes a plurality of protrusions protruding from opposite side surfaces of the coupling body and spaced apart from each other by a distance that is equal to a thickness of the protruding insertion portion so as to define at least two insertion spaces for insertion of the protruding insertion portion, so that the supply unit is coupled to the water guide as the protruding insertion portion is inserted into one of the insertion spaces. a tub providing a washing space; a door provided on a front of the tub for opening or closing the washing space; a sump provided under the tub for storing wash water; a rack provided so as to be pulled from the tub for accommodating an object to be washed; a spray arm for spraying wash water to the object to be washed; a water guide including a supply flow-path for communicating with the sump, the supply flow-path being provided inside the tub for providing a flow-path for movement of the wash water from an inside of the sump, and a supply port formed in one surface of the supply flow-path for supplying the wash water; a supply unit including a support body provided with a communication hole for communicating with the supply port in order to receive the wash water, a connection pipe extending from the support body for transferring the wash water to the spray arm, and an spray arm coupler provided on an end of the connection pipe so as to be coupled to the spray arm; and a connection member including a coupling body having one surface coupled to the water guide and a remaining surface coupled to the support body, and a through-hole formed in the coupling body so as to communicate with the supply port, wherein the supply unit further includes at least one insertion portion protruding rearward from opposite side surfaces of the support body, and wherein the connection member includes a plurality of protrusions protruding from opposite side surfaces of the coupling body and spaced apart from each other by a distance that is equal to a thickness of the protruding insertion portion so as to define at least two insertion spaces for insertion of the protruding insertion portion, so that the supply unit is coupled to the water guide as the protruding insertion portion is inserted into one of the insertion spaces.