Small handheld electronic musical instrument and side key mechanism thereof

The utility model discloses a miniature hand-held electronic musical instrument and a side button mechanism thereof, the side button mechanism comprises a side button, a rotating shaft extending along a first direction, and an elastic buffer member, the first direction is the length direction of the housing, the side wall of the housing is provided with a button via hole for the side button to pass through and move, and the elastic buffer member is arranged on the side wall of the housing. The side key rotates around a first direction when being pressed through the rotating shaft, the elastic buffer piece and the rotating shaft are located in the shell, and the elastic buffer piece is connected with the side key and provides pressing resistance for the side key. When the side key is pressed to rotate, the side key is lifted by the pressing resistance so that the side key cannot be in contact with the light touch switch in the shell, the side key overcomes the pressing resistance to press the light touch switc