A vessel propulsion apparatus includes an exhaust passage guiding exhaust generated at an engine, a water jacket cooling at least a portion of the exhaust passage, a cooling device supplying water outside the vessel propulsion apparatus to the water jacket, an exhaust sensor detecting a concentration of a component in the exhaust in the exhaust passage, and a non-catalytic porous member disposed in the exhaust passage at an upstream side relative to the exhaust sensor. The non-catalytic porous member is a porous member that does not hold a catalyst.