A liquid feeder includes a pump which is prevented from idling, and a replenisher including a cylinder that is a bottomed tube including an opening on a side adjacent to a communication flow path, the opening being connected to the communication flow path, and that is capable of accommodating a liquid in at least a portion of the cylinder, a seal that is housed in the cylinder in a movable manner along the cylinder, and seals the liquid in the cylinder, and a pressurizer to pressurize the seal toward a pump chamber.