PROBLEM TO BE SOLVED: To emit a sound that can be heard only by a notice object person in a dialyzer.SOLUTION: A dialyzer comprises a dialyzer body 6, and a parametric loudspeaker 7 electrically connected to the dialyzer body 6. The dialyzer body 6 comprises a control part that is electrically connected to the parametric loudspeaker 7 to control an orientation direction of the parametric loudspeaker 7 and an audible sound generation position.COPYRIGHT: (C)2015,JPO&INPIT