PURPOSE: To make fully warm surroundings at person's feet when heating operation begins to be started, by a method wherein in the case where warm air obtained in a refrigeration cycle is blown into a room, the warm air is blown downward until a temperature difference between a preset temperature and room temperature reaches a specified temperature, and the warm air is obliquely blown when the temperature difference reaches the specified temperature.

CONSTITUTION: When heating operation is restarted after air-conditioning, it is decided by a control part 5 for air-flow guide plates whether a room temperature Tr by a detected signal from a room temperature-detecting device 1 is at a specified value T1, e.g. 5°C or higher. When the inside of a room is not made extremely cold and the room temperature Tr is a 5°C or higher, a timer 4 is preset at ten minutes, and when the inside thereof is made extremely cold and the room temperature Tr is below 5°C, the timer 4 is preset at twenty minutes. After the timer 4 is preset, both of an upper air-flow guide plate 6 and a lower air-flow guide plate 7 are set downward almost in vertical direction by a driving part 3 therefor. In this way, since the warm air blown through an indoor machine flows downward, it warms the surroundings of a person's feet.