A dryer is provided. The dryer may include an expansion valve that may be varied in response to changes in operation mode. The dryer may be a condensation type heat pump dryer, and, in an operation method thereof, the expansion valve may be varied according to an on/off of a solenoid valve corresponding to a selected operation mode. In a first operation mode the heater may be turned on so that heating is supplied by both the heat pump and the heater to provide for rapid drying. In a second operation mode the heater may be turned off to provide for more economical operation. By employing multiple operation modes, a required refrigerant flow rate may be controlled.