A plate body includes: a nozzle plate that is provided on an actuator plate having a plurality of channels to be filled with a liquid and has a nozzle array composed of a plurality of nozzle holes communicating separately with the plurality of channels; and a nozzle cover plate that is provided on a discharge surface of the nozzle plate from which the liquid is discharged and has an opening communicating with at least one of the nozzle holes. The opening is formed such that a direction crossing a direction of the nozzle array and a direction orthogonal to the direction of the nozzle array constitutes a longitudinal direction of the opening.