A method for controlling a compound valve of an air-conditioning apparatus comprising an outdoor unit, a plurality of indoor units, and one relay unit interposing between the outdoor unit and the indoor units, the outdoor unit and the relay unit being connected by way of refrigerant pipelines which conduct a heat-source-side refrigerant, the relay unit and the indoor units being connected by way of heat medium pipelines which conduct heat media, wherein the compound valve is provided for every one of the indoor units, the compound valve comprising; - a valve element being cylindrical-shaped and rotationally movable about a spindle thereof, for opening/closing flow paths of fluid media, wherein: - the valve element includes a partition member being planar, having a major axis in a direction along a cylindrical axis of the valve element, and separating a space of the cylindrical shape into semicylindrical shapes; - a plurality of opening portions each formed in an outer circumferential side surface of the valve element, for allowing inflow or outflow of fluid media, - a body being made hollow and coaxially placed along an outer circumference of the valve element, and having, in an outer circumferential surface of the body, a first heat-medium inflow port, a second heat-medium inflow port, a first or second heat-medium outflow port, a third or fourth heat-medium inflow port, a third heat-medium outflow port, and a fourth heat-medium outflow port; and - a motor placed in a cylindrically axial direction of the valve element and connected to the valve element, the motor being configured to for altering a relative position of the partition member with respect to the opening portions by rotationally moving the valve element, the method being characterized in that the compound valve further comprises sensors mounted at respective positions so as to be capable of measuring a temperature of a heat medium flowing into the indoor unit of an air-conditioning apparatus including the valve element and the body therein, and a temperature of a heat medium outflowing from the indoor unit, wherein said motor alters the relative position of the partition member (3 1) whose position is set as a target value in accordance with a temperature difference between temperatures of said two kinds of heat media, wherein the valve element has opening portions which communicate on a respective one-to-one basis, and is rotationally moved by the motor, with either one of the first heat-medium inflow port or the second heat-medium inflow port, and with either one of the third heat-medium outflow port or the fourth heat-medium outflow port; different kinds of heat media flow adjacently to each other bordering the partition member; and, at a same time, quantities of flows of the different kinds of heat media are controlled by altering the relative position so as to correspondingly change an opening area of one opening portion with either communicating one of the first heat-medium inflow port or the second heat-medium inflow port, and that of another opening portion with either communicating one of the third heat-medium outflow port or the fourth heat-medium outflow port. - a valve element being cylindrical-shaped and rotationally movable about a spindle thereof, for opening/closing flow paths of fluid media, - the valve element includes a partition member being planar, having a major axis in a direction along a cylindrical axis of the valve element, and separating a space of the cylindrical shape into semicylindrical shapes; - a plurality of opening portions each formed in an outer circumferential side surface of the valve element, for allowing inflow or outflow of fluid media, - a body being made hollow and coaxially placed along an outer circumference of the valve element, and having, in an outer circumferential surface of the body, a first heat-medium inflow port, a second heat-medium inflow port, a first or second heat-medium outflow port, a third or fourth heat-medium inflow port, a third heat-medium outflow port, and a fourth heat-medium outflow port; and - a motor placed in a cylindrically axial direction of the valve element and connected to the valve element, the motor being configured to for altering a relative position of the partition member with respect to the opening portions by rotationally moving the valve element, the method being characterized in that the compound valve further comprises sensors mounted at respective positions so as to be capable of measuring a temperature of a heat medium flowing into the indoor unit of an air-conditioning apparatus including the valve element and the body therein, and a temperature of a heat medium outflowing from the indoor unit, wherein said motor alters the relative position of the partition member (3 1) whose position is set as a target value in accordance with a temperature difference between temperatures of said two kinds of heat media, wherein