A cleaning blade is provided which does not cause contamination of other parts even when being stored for a long period of time in a high temperature and high humidity environment. The cleaning blade is set in an image forming apparatus employing an electrostatic transfer process, including a blade member and a support member to rub and remove residual toner remaining on a photosensitive drum provided to the image forming apparatus, in which the total amount of nitrogen-containing compounds extracted with methanol from the cleaning blade is 12 .mu.g or less per cm of the cleaning blade in its longitudinal direction.