In an image forming apparatus of the present invention, a plurality of writing electrodes 3b are supported by an elastic and flexible substrate 3a such that the writing electrodes are aligned in a plurality of rows each extending in the axial direction of the latent image carrier (in the main scanning direction). The writing electrodes 3b are each formed in, for example, a triangle and are arranged in such a manner that the orientations of the triangles of the writing electrodes are alternately inverted. In this case, one end of the triangle base of a writing electrode is overlapped with one end of the triangle base of a next writing electrode 3b, as seen in the direction perpendicular to the axial direction of the latent image carrier 2 (the rotational direction of the latent image carrier 2; the feeding direction). Therefore, this design prevents occurrence of image defect due to linear stains and allows foreign matters adhering to the surface of the latent image carrier 2 to pass through spaces between the adjacent writing electrodes 3b.