Abstract: A tuner comprising a body with a shell and a connecting part protruding from the bottom surface of the shell, wherein the connecting part is provided with a slotted hole with an opening deviating from the body; the tuner further includes a magnet and an elastic member accommodated in the slotted hole, wherein the magnet has an inner wall surrounding a magnetic hole, the elastic member is at least partially accommodated in the magnetic hole, and the elastic member is provided with a slot with an opening deviating from the body; the bottom surface of the magnet is flush with or higher than the bottom surface of the connecting part. Because of the magnet and the elastic member with a slot, the tuner can be fixed to the musical instrument by magnetic attraction or plugging, which can adapt to various installation methods and meet various use requirements of customers.