To rapidly and efficiency cool or warm the passengers respectively seated on the seats of an automobile.

For ward facing air diffusers 31L, 31R, 32L and 32R are penetrated and formed in back rest parts 29L, 29R, 30L and 30R erecting from the in-vehicle seats 25L, 25R, 26L and 26R in the automobile built and installed with an air conditioning unit A in an instrument panel 10. These air diffusers 31L, 31R, 32L and 32R and the air conditioning unit A are communicated and connected by blast ducts 35L, 35R, 36L and 36R. Dampers 37L, 37R, 38L and 38R which may be opened and closed by the passengers seated on the seats 25L, 25R, 26L and 26R are interposed and installed in mid-way of the blast ducts 35L, 35R, 36L and 36R.