Abstract: An apparatus and method of controlling a density of a dot line by enabling a user to control the density of the dot line, thereby satisfying user needs and desires regarding a printed density of the dot line that is unsatisfactory due to hardware limitations of an image forming apparatus. The apparatus to control the density of the dot line expressed by dots connecting a starting point and an end point of the dot line includes a dot line density setting unit to enable a user to set the density of the dot line created by a predetermined application program, and a dot line density controller to control a rendering module of an image forming apparatus such that the rendering module can render the dot line at a density set by the dot line density setting unit.