An automatic switch for a power circuit of a bottle container is provided. The bottle container includes a bottle body, a cover and an electronic unit for allowing an accommodating unit to be assembled between the bottle body and the cover. A liquid is received in the bottle body. A ball is disposed in a mouth at a front end of the cover, and the ball is capable of opening/closing the mouth by means of an elastic body. The elastic body has a first conductive portion and a second conductive portion. The first conductive portion is brought into electrical contact with a positive electrode (or negative electrode) of a power source of the electronic unit. The second conductive portion is located above the negative electrode (or positive electrode) of the power source of the electronic unit by a distance when the elastic body is not pressed.