An oil passage structure of a dry sump engine includes an oil recovery passage, at least one first communicating hole, and a first oil suction passage. The oil recovery passage extends in a direction in which a cylinder bank extends and is disposed so that at least part of the oil recovery passage is located outward of an external lower end portion of a valve gear chamber of a cylinder head along a junction between a side wall portion of the cylinder head and a bottom surface of the valve gear chamber in a state where the dry sump engine is mounted on a vehicle in an inclined manner. The at least one first communicating hole is provided in the side wall portion so as to connect the valve gear chamber of the cylinder head and the oil recovery passage.