A method of attaching a regulating blade made of resin to an attachment portion of a development frame which is made of resin and includes the attachment portion for attaching the regulating blade includes applying an adhesive to the attachment portion, applying a hardening accelerator to the regulating blade, and attaching the regulating blade to the attachment portion via the adhesive applied to the attachment portion and the hardening accelerator applied to the regulating blade. The regulating blade is disposed opposite to and not in contact with a development rotary member configured to bear and convey a developer toward a position at which an electrostatic image formed on an image bearing member is developed, and configured to regulate an amount of the developer to be borne on the development rotary member.