Abstract: A vertically extending air intake duct 1 on a rear of a cab 2 in a delivery vehicle to take in ambient air for an engine through an air intake 3 has a duct body 4 as outer shell with the intake 3 on an upper portion, a side branch section 5 on a lower portion of the body 4 and having upper and lower ends opened in the body 4 and outside, respectively, a mesh member 6 extending over the intake 3 to collect rainwater, a louver 7 for covering the member 6 and the intake 3 to prevent intrusion of matter other than ambient air, and a drip channel or bead 8 on an inner wall of the body 4 and just below the member 6 to capture and guide rainwater flowing down on the inner wall to the upper end of the section 5.