The ultrasonic oral cleaner has a head including an ultrasonic oscillator disposed inside a base provided with an operating portion, the base is made of a flexible material, and the base is provided with the operating portion made of the flexible material and having a smooth top surface as an ultrasonic emitting surface. In the developing unit, the agitating and conveying portion includes first and second agitating and conveying belts, each having toner agitating blades for agitating and conveying the toner. Holes are formed through the concrete around the opening and then a two part fastener is used to securely hold the sheet material. Hence, user nodes can recover distributed data based on exchanging resolution information and OID information. The transmitting device also transmits the MAC PDU indicating the feedback request information. Thus, power is conserved and user convenience is enhanced.