A novel GaN-based surface-emitting laser was realized by utilizing total internal reflection (TIR) by an inclined mirror formed at one end of the horizontal cavity of an edge-emitting laser. The inclined mirror was fabricated by focused ion beam (FIB) etching. The mirror was inclined by 45° with respect to the surface normal. The guided light propagating along the horizontal-cavity is reflected at the mirror to the surface normal. We analyzed optical losses in the laser. To increase the external quantum efficiency, removal of an FIB-damaged layer and precise control of the mirror angle are important. Argon-milling was applied to the FIB-etched surface to remove the FIB-damaged layer which causes an optical loss. The fabricated device with the stripe width of 8 Âμm and the cavity length of 600 μm lased at 390 nm with a threshold current of 260 mA. Surface-emission was obtained with beam divergence angles of 24.0° and 6.2°, corresponding to perpendicular and parallel to the junction plane, respectively. The presented surface-emitting laser is suitable to form high-power GaN-based 2D laser arrays.