A sensing element includes a plurality of sensing pixel areas arranged in matrix, wherein each of the plurality of sensing pixel areas includes a first pixel, a second pixel, a first shielding layer, a second shielding layer and at least one micro lens. The second pixel is adjacent to the first pixel in a predetermined direction. The first shielding layer is disposed on the first pixel and has a first opening, wherein an aperture of the first opening increases along the predetermined direction from a center of the first pixel. The second shielding layer is disposed on the second pixel and has a second opening, wherein a shape of the second opening is mirror symmetrical with that of the first opening in the predetermined direction. The at least one micro lens is disposed on the first shielding layer and the second shielding layer.