Ultrasonic sensor

An ultrasonic sensor configured to be attached to a vehicle body component, the ultrasonic sensor comprising:

• a sensor body having a columnar ultrasonic microphone that is provided to extend in an axial direction parallel to a center axis line and a microphone support part that supports a supported part on a proximal end side while a protrusion part protrudes on a tip end side in the axial direction of the ultrasonic microphone;
• a cushion member provided so as to surround the protrusion part of the ultrasonic microphone and formed of a synthetic resin-based elastic material into a tubular shape;
• a retainer part provided further radially outward from the center axis line than the ultrasonic microphone is, and configured to sandwich a sandwiched part on the proximal end side between the retainer part and an outer peripheral surface of the protrusion part of the ultrasonic microphone, while exposing an exposed part on the tip end side in the axial direction of the cushion member;
• and
• a waterproof seal provided in intimate contact with the exposed part of the cushion member so as to block a gap between the vehicle body component and the exposed part of the cushion member, in an on-board state in which the ultrasonic sensor is attached to the vehicle body component by inserting the protrusion part of the ultrasonic microphone and the exposed part of the cushion member into mounting holes which are through holes formed in the vehicle body component and fixing the retainer part to the vehicle body component.