To provide a double feeding detection device of ultrasonic wave type capable of ensuring sufficient number of sampling time even for a paper having small size and controlling double feeding detection with high precision.

In a double feeding detection sensor of ultrasonic wave type, a vibration stop member is arranged in close proximity to a vibration element or a member vibrating in the interlocking relationship with it and is controlled by abutting on and leaving the vibration element or the vibration member at desired timing to damp unnecessary radiation components including secondary wave and third wave following after primary wave quickly.