Provided is a liquid feed apparatus for feeding liquid by operating a diaphragm at a high frequency, in which an inlet valve and an outlet valve are integrally incorporated with a liquid feed chamber, the positions of the valve are shifted into peripheral parts of the liquid feed chamber so as to allow fluid to smoothly flow from the inlet to the outlet in order to prevent air bubbles from causing pressure fluctuation during liquid feed, from remaining in the liquid feed chamber. Further, the valve has a center beam structure in which a protrusion having a height greater than several micron meters, is formed in the seat part of the valve so as to deform a center beam for pressurizing the valve in order to enhance the shut-off ability of the valve, and the center beam has a small surface area in the direction of displacement of the valve.