PROBLEM TO BE SOLVED: To provide an ultrasonic device capable of reducing noise due to external electromagnetic waves while suppressing deterioration of acoustic characteristics, an ultrasonic apparatus, and a thickness design method.SOLUTION: The ultrasonic device includes: a substrate 411, including a first surface 411C and a second surface 411D which is a back surface of the first surface 411C, and having an opening 411A opened from the first surface 411C to the second surface 411D； a support film 412 that closes a first surface side of the opening 411A； a vibrator 413 provided on the support film 412； and a metal film 42 provided in an unopened region which is not opened with the opening 411A on the second surface 411D of the substrate 411.SELECTED DRAWING: Figure 6COPYRIGHT: (C)2018,JPO&INPIT【課題】音響特性の低下を抑制しつつ、外部電磁波によるノイズを低減可能な超音波デバイス、超音波装置及び厚み設計方法を提供する。【解決手段】第一面４１１Ｃ及び第一面４１１Ｃの裏面である第二面４１１Ｄを含み、第一面４１１Ｃから第二面４１１Ｄに亘って開口された開口部４１１Ａを備える基板４１１と、開口部４１１Ａの第一面側を閉塞する支持膜４１２と、支持膜４１２に設けられた振動子４１３と、基板４１１の第二面４１１Ｄにおいて、開口部４１１Ａにより開口されていない未開口領域に設けられた金属膜４２と、を備える。【選択図】図６
