An air conditioning system (100, 200, 300) comprising: - a refrigerant circulating path network connecting, with refrigerant lines, a compressor; - a heat-source side heat exchanger for evaporating and gasifying or condensing and liquefying a heat-source side refrigerant; - narrowing devices for controlling a flow rate of the refrigerant; - refrigerant pipes in intermediate heat exchangers for exchanging heat between the heat-source side refrigerant and a use-side heat medium; and - a refrigerant flow-path switching device for switching a circulation path of the refrigerant, for circulating the heat-source side refrigerant; and - a heat medium circulating path network connecting, with heat-medium lines, pumps for pressurizing and sending the heat medium; - use-side heat exchangers for exchanging heat between the heat medium with air in interior spaces to be air conditioned; and - heat-medium pipes in the intermediate heat exchangers, for circulating the heat medium, wherein the use-side heat exchangers control the temperatures in the interior spaces to be air conditioned by exchanging heat between the air in the interior spaces to be air-conditioned and the heat medium heated or cooled by the heat-source side refrigerant in the intermediate heat exchangers, the air conditioning system characterised by further comprising: - a plurality of integrated heat-medium flow-path switching devices connectedly interposed between the intermediate heat exchangers and the use-side heat exchangers, each integrated heat-medium flow-path switching device including thereinside: - a single drive unit concurrently for changing between the heated heat medium and the cooled heat medium and for controlling flow rate of the heated heat medium and/or the cooled heat medium; and - a single heat-medium flow-path switching valve having holes formed in its sidewall and having a longitudinal inner partition and revolved by the drive unit, wherein the single heat-medium flow-path switching valve is configured to revolve to select, for each integrated heat-medium flowpath switching device, either of the heated heat medium or the cooled heat medium for it to flow between the intermediate heat exchangers and the use-side heat exchangers, whereby air conditioning is performed. - a refrigerant circulating path network connecting, with refrigerant lines, a compressor; - a heat-source side heat exchanger for evaporating and gasifying or condensing and liquefying a heat-source side refrigerant; - narrowing devices for controlling a flow rate of the refrigerant; - refrigerant pipes in intermediate heat exchangers for exchanging heat between the heat-source side refrigerant and a use-side heat medium; and - a refrigerant flow-path switching device for switching a circulation path of the refrigerant, for circulating the heat-source side refrigerant; and - a heat medium circulating path network connecting, with heat-medium lines, pumps for pressurizing and sending the heat medium; - use-side heat exchangers for exchanging heat between the heat medium with air in interior spaces to be air conditioned; and - heat-medium pipes in the intermediate heat exchangers, for circulating the heat medium, - a plurality of integrated heat-medium flow-path switching devices connectedly interposed between the intermediate heat exchangers and the use-side heat exchangers, each integrated heat-medium flow-path switching device including thereinside: - a single drive unit concurrently for changing between the heated heat medium and the cooled heat medium and for controlling flow rate of the heated heat medium and/or the cooled heat medium; and - a single heat-medium flow-path switching valve having holes formed in its sidewall and having a longitudinal inner partition and revolved by the drive unit,