A usage-side air-conditioning apparatus comprising: a casing ; a usage-side heat exchanger , being provided inside the casing, to cool or heat air inside the casing through the use of a refrigerant supplied from a heat-source-side air-conditioning apparatus ; an air supply/exhaust mechanism to take room air into the casing from an air-conditioned space, take outdoor air into the casing from outside the air-conditioned space, supply the air inside the casing as supply air to the air-conditioned space, and exhaust the air inside the casing as exhaust air out of the air-conditioned space; and a refrigerant leakage detection device to detect the refrigerant; wherein the air supply/exhaust mechanism is configured to perform a refrigerant exhaust operation to exhaust the refrigerant out of the air-conditioned space along with the air inside the casing when the refrigerant leakage detection device has detected the refrigerant; characterized in that the usage-side heat exchanger is configured to be connected to the heat-source-side air-conditioning apparatus via a refrigerant interconnection pipe ; a joint to connect the usage-side heat exchanger to the refrigerant interconnection pipe is provided outside the casing ; the air supply/exhaust mechanism has an inside-outside communication mechanism capable of switching between an inside-outside communication state of allowing communication between the casing interior and a usage-side installation space in which the casing is to be provided, and an inside-outside non-communication state of not allowing communication between the casing interior and the usage-side installation space; and the inside-outside communication mechanism is configured to be put in the inside-outside communication state to perform the refrigerant exhaust operation. a casing ; a usage-side heat exchanger , being provided inside the casing, to cool or heat air inside the casing through the use of a refrigerant supplied from a heat-source-side air-conditioning apparatus ; an air supply/exhaust mechanism to take room air into the casing from an air-conditioned space, take outdoor air into the casing from outside the air-conditioned space, supply the air inside the casing as supply air to the air-conditioned space, and exhaust the air inside the casing as exhaust air out of the air-conditioned space; and a refrigerant leakage detection device to detect the refrigerant; wherein the air supply/exhaust mechanism is configured to perform a refrigerant exhaust operation to exhaust the refrigerant out of the air-conditioned space along with the air inside the casing when the refrigerant leakage detection device has detected the refrigerant; characterized in that the usage-side heat exchanger is configured to be connected to the heat-source-side air-conditioning apparatus via a refrigerant interconnection pipe ; a joint to connect the usage-side heat exchanger to the refrigerant interconnection pipe is provided outside the casing ; the air supply/exhaust mechanism has an inside-outside communication mechanism capable of switching between an inside-outside communication state of allowing communication between the casing interior and a usage-side installation space in which the casing is to be provided, and an inside-outside non-communication state of not allowing communication between the casing interior and the usage-side installation space; and the inside-outside communication mechanism is configured to be put in the inside-outside communication state to perform the refrigerant exhaust operation. <EOS>