In this study, we investigated and evaluated the air conditioning operation of the driver according to the temperature difference between the inside and outside of a car parked outside during the summer. We suggest including a comfort mode to the car air conditioning system to improve the thermal comfort of the driver, in which the comfort can be maintained for a longer time. For the a result of our experiment, in the cases with temperature of above $45^{circ}C$ inside of the car, the subjects preferred strong air blow with the face and the arms in the direction of the blow. In the cases with temperature of below $40^{circ}C$ inside of the car, the subjects preferred lower volume of air blow. In the temperature below $28.1^{circ}C$ inside of the car, the mean temperature on the skin of the driver reached the comfort zone.