In a III-nitride semiconductor laser device, a laser structure includes a support base comprised of a hexagonal III-nitride semiconductor and having a semipolar primary surface, and a semiconductor region provided on the semipolar primary surface of the support base. An electrode is provided on the semiconductor region of the laser structure. The c-axis of the hexagonal III-nitride semiconductor of the support base is inclined at an angle ALPHA with respect to a normal axis toward the m-axis of the hexagonal III-nitride semiconductor. The angle ALPHA is in the range of not less than 45 degrees and not more than 80 degrees or in the range of not less than 100 degrees and not more than 135 degrees. The laser structure includes first and second fractured faces that intersect with an m-n plane defined by the m-axis of the hexagonal III-nitride semiconductor and the normal axis. A laser cavity of the III-nitride semiconductor laser device includes the first and second fractured faces. The laser structure includes first and second surfaces, and the first surface is opposite to the second surface. Each of the first and second fractured faces extends from an edge of the first surface to an edge of the second surface. The support base of the laser structure has a recess provided at a portion of the edge of the first surface in the first fractured face. The recess extends from a back surface of the support base, and an end of the recess is apart from the edge of the second surface of the laser structure.