In an ejector cycle with an ejector including a nozzle for decompressing refrigerant, a variable throttle device is disposed upstream from the nozzle to decompress and expand high-pressure refrigerant flowing from a condenser. For example, the variable throttle device decompresses the high-pressure refrigerant in a gas-liquid two-phase state at an upstream position from the nozzle of the ejector. In addition, the variable throttle device includes a back pressure chamber having an inner pressure that changes by sensing a refrigerant temperature at a refrigerant outlet side of an evaporator, and a pressure introducing means for introducing a refrigerant pressure of a refrigerant outlet side of the evaporator to a side opposite to the back pressure chamber with respect to a diaphragm. Therefore, a pressure difference between the back pressure chamber and the side opposite to the back pressure chamber can be made smaller.