To provide a tuning device with which a display of a pitch error is easy to see.

The tuning device is constituted such that the pitch name decision results of the device and the calculation results of a pitch error calculating means are displayed on a light transmission type display 24 and the pitch name and the pitch error which are displayed on the light transmission type display 24 are magnified and projected through a projection lens 26 to be displayed on an arbitrary display surface. Or the tuner is constituted such that a multi-color light emitting element and a luminescent color control means are provided and the luminescent color of the multi-color light emitting element is switched according to the numeric value of the pitch error and luminescence of the multi-color light emitting element is projected on an arbitrary display surface as a luminescent point and the pitch error is displayed on the display surface by the color of the luminescent point.