Each of all ultrasound transducers constituting an ultrasound transducer group 48 of an ultrasound transmitting/receiving portion 14 is connected to a circuit board 49 via electrical wiring 50 so that all the ultrasound transducers can transmit/receive ultrasound. Therefore, even if a second ultrasound transducer group 48b which causes ultrasound to be reflected in a housing 41 occurs due to a shape (inclination and an amount of projection), influence and the like of an outer circumferential portion 42a of an opening portion 42 of the housing 41, a first ultrasound transducer group 48a capable of emitting ultrasound from the opening portion 42 is appropriately secured.
