Abstract: The improved laser line beam emitting apparatus provides reduction in the cost and a number of the parts, simplicity of the adjustment, and allows for drawing of a straight line in the range of the wide angle. It comprises a single laser beam source unit in which a cylindrical rod lens with semitransparent and complete transparent faces produces reflectively and refractively passing laser beam therefrom. The reflected and refracted laser beams diffuse in the first direction and the second direction opposite from the first direction, respectively. The diffused laser beams draw a horizontal or vertical laser line surrounding the apparatus (a straight line passing objectives ahead of, behind and opposite sides of the apparatus or passing objectives above and below the apparatus).