A developing device includes a frame (12); a developer carrying member (10d) for carrying a developer to develop an electrostatic image formed on an image bearing member, the developer carrying member including a first cylindrical portion (10d) and a second cylindrical portion (20a,20b) provided at an end of the cylindrical portion and supported by a bearing portion (21a,21b); a magnet (10c) provided in the developer carrying member, the magnet being extended from inside of the developer carrying member to outside thereof; a first electroconductive portion (28,29) supported on the magnet and extended from inside of the developer carrying member to outside thereof; a second electroconductive portion (30) provided in the developer carrying member and electrically connected with an inner surface (10d1) of the first cylindrical portion and in slidable contact inside the developer carrying member with the first electroconductive portion; in addition a third electroconductive portion (25) including a first electrical contact portion (25b) electrically connected with the first electroconductive portion outside of the developer carrying member and a second electrical contact portion (25a) disposed at a position different from the first electrical contact portion and electrically connected with an electrical contact (26) of a main assembly of an image forming apparatus; wherein a developing bias is applied to the developer carrying member from the electrical contact of the main assembly of the image forming apparatus by way of, e.g., the third electroconductive portion, the second electroconductive portion and the first electroconductive portion.