Patent ID: 7398687

Claim:
An ultrasonic sensor, comprising: a cover member having a hollow portion which defines therein a space and has an opening at one end thereof; and a sensor body having an ultrasonic transducer, an insertion part of the sensor body which includes the ultrasonic transducer being inserted in the hollow portion from the opening of the cover member, wherein: the insertion part of the sensor body is inserted in the hollow portion of the cover member from one side of a base after the cover member is inserted through a hole portion of the base from an other side of the base, so that the sensor body is attached to the base through the cover member, the one side and the other side of the base being opposite to each other; the cover member has a first engagement portion and a second engagement portion which are positioned to be opposite to each other with respect to the hollow portion of the cover member; the sensor body has a third engagement portion which is engaged with the first engagement portion, and a fourth engagement portion which is engaged with the second engagement portion; and the first engagement portion, the second engagement portion, the third engagement portion and the fourth engagement portion are arranged, in such a manner that a force applied to the cover member due to an engagement between the first engagement portion and the third engagement portion has a direction opposite to that of a force applied to the cover member due to an engagement between the second engagement portion and the fourth engagement portion when the sensor body is attached to the cover member.