A fluid tank fluid is provided which includes a bubble removing device provided therein to remove bubbles from the fluid. The bubble removing device includes a cyclone chamber for generating a swirling current in the fluid flowing therethrough to separate bubbles from the fluid. At least one outflow port is provided through which the fluid from which the bubbles have been separated flows from the cyclone chamber. And an exhaust port is provided through which the bubbles separated from the fluid are driven from the cyclone chamber.