An air conditioning unit for a vehicle includes a first channel and a second channel, a blowing unit including a first blower fan and a second blower fan that rotate together by sharing a rotary shaft and a driving unit, a bypass channel, and a control door disposed among the outlets of the first channel and the second channel, the heating core, and the bypass channel to control air discharged from the first channel or the second channel to pass through the heating core or not to pass through the heating core through the bypass channel.