An electronic apparatus and a three-dimensional input device thereof are disclosed. The electronic apparatus includes a display and the three-dimensional input device. The three-dimensional input device includes an infrared ray emitting/receiving unit, a cursor control unit and a radio frequency receiving unit. The infrared ray emitting/receiving unit is electrically connected to the display and includes an infrared ray emitter and an infrared ray receiver. The cursor control unit includes a reflective material and a radio frequency emitter. The radio frequency emitter is electrically connected to the display.