(57) The present invention relates to a nozzle assembly of a vacuum cleaner for both wet and dry cleaning. The nozzle assembly of the present invention comprises a suction head 220 installed at an end of an extension tube 210 connected to a main body of the vacuum cleaner to suck a cleaning fluid and foreign substances while moving on a floor; a sprayer 230 installed on an upper surface of the suction head 220 to spray the cleaning fluid toward a front end of the suction head 220; a nozzle cover 226 for defining, on the upper surface of the suction head 220, a spray flow passage 227 through which the cleaning fluid sprayed from the sprayer flows; downstream ribs 224 provided at a downstream side of the spray flow passage 227 defined by the nozzle cover 226 and having penetrating portions 225 allowing passage of the cleaning fluid therethrough formed at predetermined intervals between adjacent downstream ribs; and an upstream rib 240 which shields the spray flow passage 227 corresponding to a space between the sprayer 230 and the downstream ribs 224 and is formed with penetrating portions 241 at positions except a position to which the cleaning fluid sprayed from the sprayer 230 is delivered directly. According to the present invention, when a user performs wet cleaning, he/she can perform the cleaning by pushing the nozzle assembly forward. Thus, less force is required for the cleaning. Further, since the cleaning fluid sprayed from the sprayer is uniformly discharged through the entire front end of the nozzle assembly, cleaning can be more firmly performed.