A developing apparatus usable with an electrophotographic image forming apparatus for forming an image on a recording material, includes a developer carrying member for developing a latent image formed on an electrophotographic photosensitive member with a developer; a first frame for accommodating the developer, the first frame including a first opening for supplying the developer and a first connecting portion provided around first opening; a second frame containing the developer carrying member, a second opening for receiving supply of the developer from the first opening and a second connecting portion provided around the second opening; an elastomer for connecting the first connecting portion and the second connecting portion with each other with the first opening and the second opening being opposed to each other so as to permit movement of the first frame and the second frame and so as to prevent the developer from leaking between the first connecting portion and the second connecting portion.