In an intake system of a variable air-intake characteristic type for a multi-cylinder engine, an intake air-dispensing box is comprised of a dispensing box body which includes an intake air inlet, first and second intake branch pipes and one of halves of a partition wall and which has an opening provided in its outer wall opposite from the first and second intake branch pipes to extend between first and second dispensing chambers, and a lid detachably coupled to the dispensing box body to close the opening and having the other half of the partition wall. The lid is made of a light alloy by casting, and a valve bore and bearing bores for supporting a valve shaft of the on-off valve are defined in the other half of the partition wall. Thus, it is possible to carry out the maintenance of the on-off valve only by removing the lid disposed outside the intake air-dispensing box from the box, leading to an enhancement in maintenance property.