PURPOSE: To improve the degree of freedom for fitting by eliminating the need of a suction opening of an air cleaner opened to the cabin.

CONSTITUTION: A suction opening 3 of an air cleaner l is opened to the interior of a trunk room 13, a blowoff port 4 is opened to the cabin, and a blower 5 for generating an air flow directing from the suction opening 3 to the blowoff port 4 and a purifying filter 6 for purifying the air sucked through the suction opening 3 are disposed in the main body case 2. Thus, when the blower 5 is operated, the air in the cabin enters the trunk room 13 through a discharge hole 11 to be sucked through the suction opening 3 and purified by the purifying filter 6, so that the purified air is blown off from the blowoff port 4 to the interior of the cabin. Accordingly, the need of a suction opening of the air cleaner l from the interior of the cabin can be eliminated.