A gear pump is comprised of a driving gear, a first driven gear and second driven gears mutually in mesh; a housing accommodating them and defining a flow path including a first suction port, a second suction port, a first pressure port and a second pressure port; a floating comprising a thrust face bearing a floating force exerted by fluids and first, second and third pressure-receiving faces respectively oriented in a direction opposed to the thrust face; a first pressurizing chamber having fluid connection with the first pressure port or the second pressure port to exert pressure on the first pressure-receiving face; a second pressurizing chamber having fluid connection with the first suction port to exert pressure on the second pressure-receiving face; and a third pressurizing chamber having fluid connection with the second suction port to exert pressure on the third pressure-receiving face.