1. A remote control device of a heat pump system useable to switch an operating state of the heat pump system, the remote control device comprising: a touch screen: physical keys provided separately from the touch screen; and a common function setting part configured and arranged to assign the common functions to the function keys; the touch screen being configured and arranged to display a plurality of touch keys displayed by words, graphics, or symbols associated separately with any of a plurality of set items, the physical keys including at least two function keys, a number of the function keys is fewer than a number of the touch keys, the function keys being assigned a common function utilized when the operating state is switched, and the common function setting part being further configured and arranged to select any of the common functions from a storage part in which the plurality of different common functions are stored, and to assign the common function to one of the function keys.