To easily set up a drive mechanism of a temperature adjusting door member arranged in a passage for a rear seat side in the center, in an air conditioner for a vehicle partitioning inside an air conditioning case in three passages for a driver's seat side, front passenger seat side, and a rear seat side to set up the respective temperature adjusting door member in each passage.

Three passages 7 to 9 are concretely a driver's seat side air passage 7 positioned in both sides of this passage, front passenger seat side air passage 9, and the rest of the passage in the center, rear seat side air passage 8 positioned between these passages 7, 9. A first air mix door 10, 11 is set up between an evaporator 5 and a heater core 6, thereagainst, a third air mix door 12 is set up in the downstream of air from the heater core 6.