To simplify work and maintenance and to improve appearance by collecting a hot-water pump, a power source cord and a control signal line cable for connecting an indoor machine with an outdoor machine into a pipeline to be singly inserted into a through-hole and joining all these elements in a wall surface portion.

An outdoor machine 2 having a heating circuit is installed outdoors separated from a wall 1, an indoor machine 3 having a heat radiating fin or the like is arranged indoors, and these machines 2 and 3 are connected together by a pair of hot-water pipes 4a and 4b having going and returning routes. A controller 5 installed outdoors is connected to a remote-control terminal 6 provided indoors by a plurality of control signal cables 7. Power is supplied to this controller 5 by a power source cord 8 connected to an indoor commercial power receptacle. Then, the hot-water pipes 4a and 4b, the control signal cables 7 and the power source cord 8 are all collected in a single connection box 9 attached to the wall 1, and these are joined in the connection box 9.