A pair of intake collectors (1A, 1B) separated by a partition (4A) aspirates air into each cylinder of a multi-cylinder internal combustion engine via branch pipes (3A-3F). A valve (8A, 8B) which shuts off the air flow between the intake collectors (1A, 1B) is fitted onto the partition (4A) via a valve frame (11) and a bearing boss (16A) provided on the valve frame (11). An edge of the partition (4A) is fitted into a groove (18) formed on the outer circumference of the valve frame (11) so as to prevent air from leaking through an engaging part between the partition (4A) and the valve frame (11) due to a Labyrinth effect. Further, an elastically connecting member (20) disposed on both sides of the bearing boss (16A) elastically connects the valve frame (11) and the groove (18), thereby preventing relative oscillation between the partition (4A) and the valve frame (11).