A heat pump cycle capable of switching an operation mode to a cooling operation mode, a heating operation mode, and a dehumidifying-heating operation mode, and applicable to an air conditioning device, the heat pump cycle comprising: a compressor sucking, compressing and discharging a refrigerant; a first usage side heat exchanger (12, 52) making a high pressure refrigerant discharged from a discharge port of the compressor exchange heat with air to be blown into a space to be air-conditioned or exchange heat with a heating medium for heating the air; a first pressure reducing portion configured to reduce pressure of the refrigerant flowing out of the first usage side heat exchanger (12, 52); a gas-liquid separation portion (14, 54, 55) separating gas and liquid of the refrigerant having passed through the first pressure reducing portion; a second pressure reducing portion (16b, 17, 18) configured to reduce pressure of a liquid-phase refrigerant separated by the gas-liquid separation portion (14, 54, 55); an outside heat exchanger making the refrigerant passing the second pressure reducing portion (16b, 17, 18) exchange heat with an outside air; a second usage side heat exchanger making the refrigerant exchange heat with the air to be blown into the space and making the refrigerant flow out toward a suction port of the compressor; a third pressure reducing portion reducing pressure of the refrigerant flowing into the second usage side heat exchanger; an intermediate pressure refrigerant passage guiding a gas-phase refrigerant separated by the gas-liquid separation portion (14, 54, 55) to an intermediate pressure port provided in the compressor to thereby mix the gas-phase refrigerant with the refrigerant in a compression process of the compressor; and a refrigerant flow passage switching device (16a, 16c) switching a refrigerant flow passage of the refrigerant circulated in the cycle, characterized in that each of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) is configured to be set not only in a throttled state in which each of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) performs a pressure reducing operation but also in a fully open state in which each of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) does not perform the pressure reducing operation, wherein in the heating operation mode, both of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) are set in the throttled state, in the cooling operation mode, both of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) are set in the fully open state, and in the dehumidifying-heating operation mode, at least one of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) is set in the fully open state. a compressor sucking, compressing and discharging a refrigerant; a first usage side heat exchanger (12, 52) making a high pressure refrigerant discharged from a discharge port of the compressor exchange heat with air to be blown into a space to be air-conditioned or exchange heat with a heating medium for heating the air; a first pressure reducing portion configured to reduce pressure of the refrigerant flowing out of the first usage side heat exchanger (12, 52); a gas-liquid separation portion (14, 54, 55) separating gas and liquid of the refrigerant having passed through the first pressure reducing portion; a second pressure reducing portion (16b, 17, 18) configured to reduce pressure of a liquid-phase refrigerant separated by the gas-liquid separation portion (14, 54, 55); an outside heat exchanger making the refrigerant passing the second pressure reducing portion (16b, 17, 18) exchange heat with an outside air; a second usage side heat exchanger making the refrigerant exchange heat with the air to be blown into the space and making the refrigerant flow out toward a suction port of the compressor; a third pressure reducing portion reducing pressure of the refrigerant flowing into the second usage side heat exchanger; an intermediate pressure refrigerant passage guiding a gas-phase refrigerant separated by the gas-liquid separation portion (14, 54, 55) to an intermediate pressure port provided in the compressor to thereby mix the gas-phase refrigerant with the refrigerant in a compression process of the compressor; and a refrigerant flow passage switching device (16a, 16c) switching a refrigerant flow passage of the refrigerant circulated in the cycle, characterized in that each of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) is configured to be set not only in a throttled state in which each of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) performs a pressure reducing operation but also in a fully open state in which each of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) does not perform the pressure reducing operation, wherein in the heating operation mode, both of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) are set in the throttled state, in the cooling operation mode, both of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) are set in the fully open state, and in the dehumidifying-heating operation mode, at least one of the first pressure reducing portion and the second pressure reducing portion (16b, 17, 18) is set in the fully open state.