A wearable device includes a case and a far infrared temperature sensing device. The case has a first opening. The far infrared temperature sensing device is disposed inside the case of the wearable device. The far infrared temperature sensing device includes an assembly structure, a sensor chip, a filter structure, and a metal shielding structure. The assembly structure has an accommodating space and a top opening. The sensor chip is disposed in the accommodating space of the assembly structure. The filter structure is disposed above the sensor chip. The metal shielding structure is disposed above the sensor chip, and has a second opening to expose the filter structure. The first and second openings are communicated to cooperatively define a through hole.