A gas-liquid separator for use in portable equipments, that can be made small, has a simple structure, can be manufactured at low costs, and carries out separation of gas and liquid with no problems occurring even if there is a change in orientation. The gas-liquid separator receives gas-containing liquid mixed with gas and performs gas-liquid separation into gas and liquid, and includes a gas-liquid separation chamber (8) for performing gas-liquid separation when gas-containing liquid is fed between a liquid extracting member (4) for passing the liquid therethrough while restricting the passage of gas therethrough and a gas extracting member (9) for passing gas therethrough while restricting the passage of liquid therethrough. The height (14) of the gas-liquid separation chamber (8) is set at not more than a maximum bubble growth diameter in the direction of gravity which depends on the surface tension of liquid. Thus, even when the gas-liquid separator is orientated such that the gas extracting member (9) is at the bottom in the direction of gravity, the liquid will not cover the gas extracting member (9) due to gravity and the outlet for gas will not be lost.