A liquid separator including a cylindrical closed container in which a refrigerant is stored, a refrigerant inflow pipe that allows the refrigerant to flow into the closed container, and a refrigerant outflow pipe that allows the vapor-phase refrigerant in a space inside the closed container to flow out, in which the refrigerant inflow pipe and the refrigerant outflow pipe are each connected from the upper part of the closed container toward the inside thereof, and the closed container has a short cylindrical shape in which the height is smaller relative to the diameter.