A charging brush unit includes a brush and a conductive holder. The brush includes a plurality of flexible conductive fibers. The plurality of flexible conductive fibers is supplied with a charging bias to generate electrical discharge between a top of the plurality of conductive fibers and a latent image carrier across a gap formed between the top of the plurality of conductive fibers and the latent image carrier. The gap is provided with an electrode. The electrode includes a plurality of openings opposing the top of the plurality of conductive fibers and is supplied with a bias different from the charging bias applied to the plurality of conductive fibers. The conductive holder holds the brush.