To provide the breather structure capable of surely preventing leakage of the liquid housed in a housing space outside and being easily manufactured with a small number of man-hours.

The breather structure is formed of a base, a port part integrally formed with the base, and a baffle member separately formed from the base. An air flow passage inside the port part is divided to be bent by a projecting wall of the baffle member, and a ventilation hole for communicating with housing space with inside the port part is provided between an outer edge of a lower end of the port part and a bottom plate of the baffle member. The bottom plate shields intrusion of the liquid housed in the housing space into the port part, and the projecting wall shields flow-out of the liquid intruding into the port part outside to prevent leakage of the liquid outside. The breather structure can be easily manufactured with a small number of man-hour by separately forming the baffle member from the base and assembling it in the base for integration.