An ejector for a vapor compression system using a swirl flow includes an ejector body comprising a main inlet into which a main flow in high pressure flows, a nozzle section in fluid communication with the main inlet, a mixing portion in fluid communication with the nozzle section, a diffuser in fluid communication with the mixing portion, and a discharge portion in fluid communication with the diffuser. A suction pipe is inserted in a center of the ejector body and includes a through-hole into which a suction flow in low pressure flows and a leading end portion of an outer surface of the pipe forms a plurality of inclined passages with the nozzle section of the ejector body. These passages allow the main flow to be moved to the mixing portion so as to form a swirl flow between the main flow and suction flow when mixed in the ejector.