A breather device for an outboard motor engine, the outboard motor engine including a breather chamber formed in an engine main body, and an intake passage guiding air into the engine main body, in which an intake port of the intake passage is open inside an engine cover that covers the engine main body, the breather device includes a resonator chamber communicating with an upstream side of the intake passage, and a breather passage extending from the breather chamber and communicating with the resonator chamber.