The present invention relates to a blower for air conditioner of automotive vehicles capable of striving to increase the blowing volume and reduce noise, and simplifying the structure of the blower by distributing the air come into the inside of an intake duct effectively to an upper blowing wheel and a lower blowing wheel.The blower for air conditioner of automotive vehicles comprises a scroll case formed with upper/lower suction openings at the upper/lower surfaces and a discharge opening at one side; a double suction type centrifugal fan mounted rotatably at the scroll case, and having the upper/lower blowing wheels integrated with a hub plate in the opposite direction, to which a motor is connected; an intake duct with inside/outside air suction openings and an intake door for controlling the opening degree of the inside/outside suction openings, and forming an upper air passage and a side air passage for distributing the air sucked through the inside/outside air suction openings toward the upper/lower suction openings, wherein, a ratio of an air suction cross-sectional area S1 of the upper suction opening versus a cross-sectional area S2+S3 of the side air passage is 6:4˜8:2.