A light module is disclosed. The light module includes a first printed circuit board, a second printed circuit board, a light source, and a fixing casing, wherein the first printed circuit board and the second printed circuit board each has a fixing part, and the fixing part of the second printed board is attached to the fixing part of the first printed board. The light source is disposed on the first printed circuit board to couple to the first printed board and the second printed board. The fixing casing has a contact surface. When the fixing casing is fixed onto the fixing parts of the second printed circuit board and the first printed circuit board, the contact surface contacts the fixing part so that the second printed circuit board is clamped between the contact surface and the first printed circuit board.