A support member for supporting a cleaning blade of an upstream side is arranged between a charging roller of an image forming unit of the upstream side and a developing sleeve of an image forming unit of a downstream side. The support member is formed using a conductive member (metallic plate), is arranged to completely go across a tangent between the charging roller and the developing sleeve, and is grounded. Even when a developing bias is applied to the developing sleeve during application of a charging bias to the charging roller, the support member can function as a shielding member to prevent noise in the charging bias, which makes it possible to reduce a distance between the image forming units.