PURPOSE: To dispense with an outside air guide port for a storage cover by opening the storage cover when the outside air is introduced into an air conditioner or a wiper is used, and forming the outside air guide port or a wiper rotation space between the storage cover and a front window panel.

CONSTITUTION: A cowl top panel 25 with an outside air vent port as an outside air flow path is connected on a dash upper panel 24 fitted with an air conditioner 36 at an air intake port 24a to constitute an air box with a nearly box- shaped cross section, the cowl top panel 25 is formed into a recessed shape, and a storage section 27 to store a wiper 26 is formed. The opening/closing device 29 of a storage cover 28 is fitted to the storage section 27. The opening/ closing device 29 has a lever 33 rotated by the drive of a motor 30, and the storage cover 28 is opened or closed by the rotation of the lever 33 via a support shaft 28c supporting, at one end, a pulley 34a slidable along a vertical slit 31a and a horizontal slit 31b provided on a guide plate 31.