PURPOSE: To allow the air quantity distribution of a foot blowoff port, a defroster blowoff port and a side face blowoff port provided at a duct to be adjusted to the specified specification value.

CONSTITUTION: The lower reaches end of a duct 2 is provided with a defroster blowoff port 6, a center face blowoff port 7, a side face blowoff port 8 and a foot blowoff port 9. The defroster blowoff port 6 and the center face blowoff port 7 are opened/closed by a common defroster-face door 14, and the foot blowoff port 9 is opened/closed by a foot door 15. Inside the duct 2 provided with the respective blowoff ports 6-9, a partition plate is extended from the upper reaches of the defroster blowoff port 6, that is, the upper wall of the duct 2 to which the defroster blowoff port 6 is opened, toward the lower wall of the duct 2 to which the foot blowoff port 9 is opened. This partition plate can almost cut off the flow of air passing through the tip side of the foot door 15 when the foot blowoff port 9 is placed in the fully opened state by the foot door 15.