In an image forming apparatus, the workability of assembling of a cleaning blade is improved, and the dimensional accuracy between the cleaning blade and a photosensitive member is properly ensured. A cleaning blade 19 having a body portion 19a configured by an elastic plate member and a planar base plate portion 19b to which the body portion 19a is secured is held and secured by: a first butting part P1 which is a predetermined position in a first face S1 positioned in a front portion of the base plate portion 19b in the rotation direction of a photosensitive drum 2a to 5a; a second butting part P2 which is in a second face S2 opposed to the first face S1, and which is positioned closer to the photosensitive drum 2a to 5a than the first butting part P1; a third butting part P3 which is an end part of the base plate portion 19b that is opposite to the photosensitive drum 2a to 5a; and the photosensitive drum.