An image forming apparatus includes an image bearing drum; an exposing unit for exposing the drum; an electric circuit board provided substantially perpendicularly to an apparatus installing floor; a driving unit for supplying a driving force; a first metal plate supporting the exposing unit; a second metal plate supporting the electric circuit board; and a third metal plate supporting the driving unit. At least one of the first, second and third plates is provided at each of four sides of the apparatus, the four sides being substantially perpendicular to the floor. The first, second and third plates are electrically connected with each other.