MUSICAL INSTRUMENT TUNER, PERFORMANCE SUPPORT DEVICE AND MUSICAL INSTRUMENT MANAGEMENT DEVICE

A musical instrument tuner capable of providing satisfactory usability and performing stable and accurate tuning is provided. The musical instrument tuner includes: a sensor device that is attached to a musical instrument; and an operation device that is able to perform wireless communication mutually with the sensor device, in which the sensor device includes an acceleration sensor that has at least two detection axes, frequency detection means for detecting, as a detected frequency, a frequency of a vibration of musical sound generated through an operation of the musical instrument based on an output from the acceleration sensor, and sensor-side communication means for transmitting transmission information including information regarding the detected frequency to the operation device, and the operation device includes operation-side communication means for receiving the transmission information transmitted from the sensor device, display means, and control means for generating tuning information of the musical instrument and causing the display means to display the tuning information based on the transmission information received from the sensor device.