The invention provides an ultrasonic device, which can solve the problem that foreign matters such as paper powder are accumulated on transmitting and receiving surfaces of ultrasonic waves and the problem that the transmitting sensitivity or receiving sensitivity of the ultrasonic waves is reduced. The ultrasonic device includes an ultrasonic element that performs at least one of transmitting anultrasonic wave along a first axis and receiving the ultrasonic wave input along the first axis, and a protective member that is provided on the first axis and covers the ultrasonic element, in whichthe protective member has a plurality of pores through which the ultrasonic wave traveling along the first axis passes.