To provide a tuning device for outputting musical sound with a stable pitch, by correcting the pitch of an input musical sound signal when tuning a musical instrument, even when the sound is untuned.

The tuning device comprises: a pitch detecting section 2 for detecting the pitch of the signal input from an input section 1; a pitch monitoring section 3 for monitoring the detected pitch; a control section 4 for controlling a correction part between the pitch detected by the pitch detecting section 2 and a reference pitch of the pitch monitoring section 3; a musical sound correction section 5 for correcting the pitch according to the correction amount of the pitch controlled by the control section 4. The musical sound signal with pitch is corrected by the musical sound correction section 5, is output by an output section 11.