The object of the present invention is to provide a data decision apparatus and an error measurement apparatus which can set the phase of the clock to the optimum state with respect to the data signal without continuously sweeping of the phase, and can keep the state for a long time. A user record is that includes anatomical information relating to an ear of a user is received. By the action of the component, combustion residues can be solidified to form a slag, thus preventing formation of mist.