A beverage container is configured to prevent a beverage from leaking out even when a user tilts the container, and to allow the user to easily drink the beverage even when pressure within the container is negative. The beverage container can include a container main body, a base member, and a cap body. The base member can have a vent for regulating a pressure variation in the container main body, and a ventilation valve for introducing air from the outside when the pressure within the container main body becomes negative in relation to the outside pressure and capable of preventing leakage of a liquid beverage contained in the container main body. The cap body can include a ventilation open/close hood capable of changing the state of the vent to a ventilation state or a closed state. The ventilation open/close hood can be configured to bring the vent into the closed state when in a portable state such as when the user carries the beverage container, and to bring the vent into the ventilation state when in an operating state.