The tuning device also includes an input unit for inputting a sound of an
instrument to be tuned or a musical sound signal, a conversion
information storing portion in which a plurality of pieces of information
on filters for tuning are stored, a control unit for extracting the piece
of information on an arbitrary one of the filters from the conversion
information storing portion, and a conversion unit for converting a
signal of the input unit into a signal of an arbitrary frequency band in
response to a signal from the control unit. Owing to this structure, even
if ambient noise has mixed with a sound of the instrument to be tuned,
the sound is filtered into a signal component of a target scale or a
target pitch name. By extracting a pitch from this signal component, the
number of erroneous tuning operations can be reduced.