Exhaust device for four-cylinder internal combustion engine

An exhaust device for a four-cylinder internal combustion engine, the internal combustion engine having first to fourth cylinders, at least one pair of which are 360° apart in ignition timing,

• the exhaust device comprising:
• a collective exhaust port into which exhaust ports of the one pair of cylinders merge together inside a cylinder head, the collective exhaust port having an opening at one side surface of the cylinder head;
• and
• a collective exhaust pipe joined to the collective exhaust port, the collective exhaust pipe and an exhaust pipe for other one of the cylinders being connected to a single catalytic converter,
• wherein an equivalent diameter of the opening of the collective exhaust port is larger than equivalent diameters of the exhaust ports of the one pair of cylinders before merging;
• wherein the opening of the collective exhaust port has an elliptical or elongated circular shape along a cylinder row direction such that a short diameter, which is along a direction perpendicular to the cylinder row direction, of the opening of the collective exhaust port is smaller than the equivalent diameters of the exhaust ports of the one pair of cylinders before merging.