An intake system for with an internal combustion engine, having a plurality of intake valves for one cylinder, includes a plurality of intake ports, opening into a combustion chamber, with openings which extend toward one side of the internal combustion engine. At least one exhaust port, opening into the combustion chamber, has an opening which extends toward another side of the engine, and is formed in the cylinder head on the other side, which is opposite to the one side of the internal combustion engine. The intake ports are arranged so that the center intake port is inclined at an angle larger than an angle at which other, side intake ports are inclined, so as to direct fuel mixture flows, introduced through the side intake ports, toward an inner surface of the cylinder bore above a top of the piston at a lower dead point.