A pump comprising: a flat plate-shaped member including: a vibrating plate in which a piezoelectric element is disposed on one principal surface, a support plate, and a support member that connects an outer edge of the vibrating plate and the support plate and supports the vibrating plate so that the vibrating plate is configured to vibrate in a principal surface direction; a flow path forming member disposed so as to face the flat plate-shaped member; a pump chamber formed to be surrounded by the flat plate-shaped member, the flow path forming member, and a side wall member connected to the flat plate-shaped member and the flow path forming member; an annular film valve fixed to the flat plate-shaped member or the flow path forming member and disposed in the pump chamber so as to overlap the vibrating plate in a plan view; a vent hole formed in the flat plate-shaped member or the flow path forming member; and a further vent hole formed in the flow path forming member, wherein the vent hole in the flat plate-shaped member or in the flow path forming member and the further vent hole in the flow path forming member are disposed at positions where the annular film valve is placed therebetween in a plan view, and the annular film valve changes a flow path resistance between the vent hole in the flat plate-shaped member or in the flow path forming member and the further vent hole in the flow path forming member in accordance with a vibration of the vibrating plate, wherein an opening of the annular film valve overlaps said further vent hole in the flow path forming forming member in a plan view. a flat plate-shaped member including: a vibrating plate in which a piezoelectric element is disposed on one principal surface, a support plate, and a support member that connects an outer edge of the vibrating plate and the support plate and supports the vibrating plate so that the vibrating plate is configured to vibrate in a principal surface direction; a vibrating plate in which a piezoelectric element is disposed on one principal surface, a support plate, and a support member that connects an outer edge of the vibrating plate and the support plate and supports the vibrating plate so that the vibrating plate is configured to vibrate in a principal surface direction; a flow path forming member disposed so as to face the flat plate-shaped member; a pump chamber formed to be surrounded by the flat plate-shaped member, the flow path forming member, and a side wall member connected to the flat plate-shaped member and the flow path forming member; an annular film valve fixed to the flat plate-shaped member or the flow path forming member and disposed in the pump chamber so as to overlap the vibrating plate in a plan view; a vent hole formed in the flat plate-shaped member or the flow path forming member; and a further vent hole formed in the flow path forming member, wherein the vent hole in the flat plate-shaped member or in the flow path forming member and the further vent hole in the flow path forming member are disposed at positions where the annular film valve is placed therebetween in a plan view, and the annular film valve changes a flow path resistance between the vent hole in the flat plate-shaped member or in the flow path forming member and the further vent hole in the flow path forming member in accordance with a vibration of the vibrating plate,