An air-conditioning apparatus for a vehicle, in which a temperature in a vehicle interior is automatically adjusted under a stable driving mode in which a difference between the temperature in the vehicle interior and a set temperature is lesser than a predetermined value or a transitional driving mode in which the difference is larger than the predetermined value so that the temperature in the vehicle interior approaches to the set temperature when an amount of solar radiation in the vehicle interior is one of parameters, the apparatus including a detecting device provided in the vehicle interior and configured to detect the amount of solar radiation, and a correcting device for correcting the amount of solar radiation detected by the detecting means to obtain a corrected amount of solar radiation, the corrected amount of solar radiation being used as a parameter of the amount of solar radiation for adjusting the temperature in the vehicle interior, under the stable driving mode.