An electronic device includes an outer case, a circuit substrate, a thermopile sensor chip, a filter structure, and a waterproof structure. The outer case has an opening. The circuit substrate is disposed inside the outer case. The thermopile sensor chip is disposed on the circuit substrate. The filter structure is disposed above the thermopile sensor chip. The waterproof structure is surroundingly connected between the filter structure and the outer case for sealing up the opening of the outer case, wherein the waterproof structure has a through hole for exposing the filter structure and communicated with the opening of the outer case.