A multi-functional device comprising an image forming apparatus to form a printing image and a scanner module to scan an image in a first scanning direction. The scanner module includes an illuminator to illuminate a light to a document mount, a sensor unit to read an image information of an object placed on the document mount, and an imaging lens which is disposed between the document mount and the sensor unit and focuses the light reflected from the object onto the sensor unit. The illuminator includes a light source to emit light, a light guiding unit which is lengthened in a second scanning direction, faces the document mount and changes a traveling path of the light emitted from the light source to illuminate the document mount, and a guide holder which comprises an installation part where the light guiding unit is installed, and a mounting part where the light source holder is mounted to provide the light source at least one side of the light guiding unit.