Button assembly and electronic device

An electronic device, comprising:

• a conductive casing, wherein two opposite sides of the conductive casing have a first opening and a second opening respectively, and the first opening is communicated with the second opening;
• a button assembly, installed at the conductive casing, and comprising:
• a conductive button, comprising a button part and a shaft part connected to the button part, wherein the button part corresponds to the first opening, and the shaft part passes through the second opening from the first opening;
• a first insulating sleeve, comprising a first shaft hole and a first lateral slit communicated with the first shaft hole, wherein the first insulating sleeve is sleeved on the shaft part through the first shaft hole and located at the first opening;
• and
• a second insulating sleeve, comprising a second shaft hole and a second lateral slit communicated with the second shaft hole, wherein the second insulating sleeve is sleeved on the shaft part through the second shaft hole and located at the second opening, wherein the second insulating sleeve comprises a second seat part abutting against the conductive casing and a second sleeve part connected to the second seat part, the second sleeve part is inserted into the second opening, the second shaft hole penetrates through the second seat part and the second sleeve part in an axial direction, the second lateral slit penetrates through the second seat part and the second sleeve part outwardly from an inner wall surface of the second shaft hole, an outer diameter of the second seat part is larger than an outer diameter of the second sleeve part and an inner diameter of the second opening, and the outer diameter of the second sleeve part is smaller than the inner diameter of the second opening;
• a circuit board, disposed in the conductive casing and corresponding to the second opening;
• and
• a conductive elastic piece, disposed between the second insulating sleeve and the circuit board, wherein the shaft part extends toward the circuit board, and the conductive elastic piece electrically contacts the shaft part and the circuit board.