An electrostatic ultrasonic transducer that includes: a first electrode that is formed with a plurality of holes; a second electrode that is formed with a plurality of holes, and is used in pair with the first electrode; an oscillation film formed with a conductor layer that is sandwiched between the pair of electrodes, and the conductor layer is applied with a direct-current (DC) bias voltage; and a retention member that keeps hold of the pair of electrodes and the oscillation film. In the transducer, an alternating signal is applied between the pair of electrodes, and the pair of electrodes each have a thickness t of about (λ/4)·n (where λ denotes a wavelength of ultrasound, and n denotes a positive odd number).