A developing device for developing with a developer a latent image formed on an image bearing member includes a container for containing the developer; a stirring member, rotatably supported by the container, for stirring the developer in the container; a magnetic member for forming a magnetic field in a gap between the container and a rotation shaft located at an end portion of the stirring member so as to magnetically confine magnetic particles in the gap; a seal member, provided outside the magnetic member with respect to a rotation shaft direction of the stirring member, contacting a peripheral surface of the rotation shaft of the stirring member; and a non-magnetic preventing portion, provided between the magnetic member and the seal member, for preventing the magnetic particles confined by the magnetic member from spreading toward the seal member.