A developing device includes: a developer container for containing developer; a developer bearing body for bearing the developer; a charging member for charging the developer bore by the developer bearing body by abutting against the developer bearing body; a supporting member for supporting the charging member; and a sealing member that is for preventing the developer from spilling from the developer container and that is provided in a state in which the side of one end thereof is compressed by the developer container and the charging member and the side of the other end thereof is compressed by the developer container and the supporting member, wherein a degree of compression of the sealing member on the side of the other end is smaller than a degree of compression of the sealing member on the side of one end.