To provide an engine with a water injector, suppressing a reduction in lubrication capacity with respect to components composing the engine.

In this engine 1-1 with the water injector, even if water injected into an intake path 102 is entered into an oil path 12 after being supplied into a combustion chamber 10 and adhering to an oil film formed on the inner peripheral surface of the combustion chamber 101, water is separated from oil flowing in the oil path 12 by an oil/water separator 13 disposed in the oil path 12. Therefore, it is possible to suppress a reduction in viscosity of oil supplied to the components composing the engine 10. Then, it is possible to suppress the reduction in the lubrication capacity with respect to the components composing the engine 10.