An ejector and a refrigeration cycle apparatus having an ejector are provided. The ejector may include an ejector body having a suction portion into which a high pressure refrigerant and a low pressure refrigerant may be suctioned, and having a mixing portion provided at one side of the suction portion and configured to mix the high pressure refrigerant with the low pressure refrigerant; a nozzle movably provided in the suction portion, and configured to inject the high pressure refrigerant; a needle inserted into an end of the nozzle and configured to control a flow sectional area of the nozzle; and a nozzle drive configured to drive the nozzle so as to be relatively movable with respect to the mixing portion and the needle. As a flow sectional area of a high pressure refrigerant passage and a flow sectional area of a low pressure refrigerant passage are controlled, a driving efficiency of the ejector may be enhanced.