An exhaust apparatus for an internal combustion engine includes a first exhaust collecting section, a first exhaust passage, a first exhaust sensor, and a rib. The first exhaust passage is connected to the first exhaust collecting section and has a curved shape to change a flow direction of the exhaust gas from a direction in which the exhaust gas is ejected from each of first cylinders. The first exhaust passage includes an outer wall provided on a radially outer side of the curved shape. The rib is provided on the outer wall of the first exhaust passage and extends along a direction perpendicular to a direction in which the exhaust gas flows. The rib is positioned downstream from the first exhaust sensor.