A device for increasing the luminous flux per unit area with the ability to reduce the light-taking distance in respect to the opposite light source of the present invention mainly comprises a front lens part, a rear lens part, an axial mutually-perpendicular bi-axial support, a movable support, a fixed base, dampers for automatically limiting tilt speed, tilt gravity generators and photoelectric conversion array, etc. Based on the principle of light group field effect, the device can increase the luminous flux and light intensity per unit area of excident light by use of lens array group so that the photoelectric conversion system is able to get more light energy. The device is able to automatically keep pace with the motion of the sun in two dimensions without measuring sensors. The device is mainly applied in solar energy photovoltaic generating technology and recycling of different light energies.