An exhaust-gas introducing passage is branched, on an outlet side of a valve, into parts, correspondingly to the number of an exhaust port of an internal combustion engine and the branching section is located at a position directly opposed to a movable valving element of the valve so as to cause exhaust gas to easily flow only in the direction of the outlet, which has introducing passages of exhaust gas communicating with a plurality of intake ports of the internal combustion engine to approach as near as possible a state in which each of the introducing passages is isolated from another introducing passages, and they assume an aspect just as if the introducing passages do not substantially communicate with one another.