A developing device for use with an image forming apparatus, includes: a developer carrying member for carrying a developer; a developer regulating member for regulating an amount of the developer carried on the developer carrying member; a first frame for supporting the developer regulating member; a fixing member for fixing the developer regulating member to the first frame; a second frame mounted to the first frame; and a molded resin portion formed by injecting a melted resin material into a space defined by the first and second frames. The molded resin portion is engaged with a first limiting portion provided as a part of the fixing member and projected into the space and is engaged with a second limiting portion provided as a part of the second frame to connect the first and second frame.