To uniform an indoor temperature by utilizing difference in specific gravity of warm air and cold air.

This room temperature uniforming device is constituted by installing a duct pipe 5 opened at its upper end and a lower end into a room 1, from a ceiling 2 to a floor 3, and a fan 8 is mounted on a part of the duct pipe 5, so that the cold air at a lower layer in the room 1 is delivered to an upper layer in the room 1 near the ceiling 2. Alternatively, with the same constitution, hot air at the upper layer in the room 1 is delivered to the lower layer in the room 1 near the floor 3. Further the fan 8 is mounted on a part of the duct pipe 5, to suck and mix the cold air at the lower layer in the room 1 and the warm air at the upper layer in the room 1 in the duct pipe 5, and to deliver the same from a discharge opening 9 at a central portion of the duct pipe 5 into the room 1.