The invention discloses a buffering device, and the buffering device is disposed on a keyboard musical instrument. The keyboard musical instrument is provided with a main body and a keyboard cover which can rotate relative to the main body. The buffering device can achieve the miniaturization of the keyboard musical instrument, and can be designed easily. The buffering device (10) is provided with an arm part (12), and a base end part (31) is supported to rotate freely relative to the main body of the keyboard musical instrument. A front end part (32) abuts against the back of the keyboard cover. The buffering device (10) is also provided with a rotating damper (13) which applies a braking force to the arm part (12) for rotation and movement; a coil spring (14) which applies a force to the arm part (12) along a first rotation direction, so as to enable the arm part (12) to be pressed towards the keyboard cover.