A washing machine includes a cabinet; a tub which is disposed in the cabinet and in which washing water is stored; a drain hose that guides the washing water in the tub toward an outer side of the cabinet; and a siphonage prevention unit disposed on the drain hose, wherein the siphonage prevention unit includes: a connection pipe having a connection flow path that communicates with the drain hose; an air pipe having an air flow path that communicates with the connection flow path; and a protrusion that is disposed adjacent to a communication portion in which the connection flow path and the air flow path communicate with each other and that protrudes from an inner side surface of the connection pipe. Through this configuration, a siphonage phenomenon in the drain hose can be prevented.