A developing device for developing with developer an electrostatic image formed on an image bearing member includes a developer carrying member; a developing chamber in which the developer carrying member is provided; a developer accommodating chamber, for accommodating developer to be fed to the developing chamber; a shaft rotatably supported in the accommodating chamber; a developer feeding member, mounted on the shaft; a light transmitting member for permitting light to pass into the accommodating chamber to detect an amount of the developer in the accommodating chamber; and a developer scattering preventing member provided on an inner wall of the accommodating chamber so as to overlap with the light transmitting member with respect to an axial direction of the shaft as seen in a direction perpendicular to the developer scattering preventing member, an upper end of the developer scattering preventing member being located below the light transmitting member.