Embodiments of the invention provide an optical semiconductor-based tube type lighting apparatus capable of enlarging light distribution to have improved assembly characteristics. The lighting apparatus includes an elongated light-transmitting tube; a linear slit formed on the light-transmitting tube in a longitudinal direction thereof; and at least one bar-shaped optical semiconductor module secured to the light-transmitting tube, with edges of the slit fitted into side surfaces of the bar-shaped optical semiconductor module. Here, the optical semiconductor module includes a heat sink, a PCB attached to the heat sink, and an array of semiconductor optical devices arranged on the PCB. The heat sink is partially exposed from the light-transmitting tube through the slit.