A cartridge mountable, along a predetermined mounting path, to a main assembly of the electrophotographic image forming apparatus including a main assembly driving shaft, said cartridge comprising: a photosensitive member on which a latent image is capable of being formed; a developer carrying member capable of developing the latent image; a coupling member (180, 980) capable of inclining relative to a rotational axis of said developer carrying member, wherein said coupling member (180, 980) is capable of taking a reference attitude in which the drive transmission is capable from the main assembly driving shaft to said developer carrying member when said developer carrying member is in a developing position in a state that said cartridge is mounted at an end portion of the mounting path, and an at-mounting attitude inclined relative to the rotational axis of said developer carrying member to engage with the main assembly driving shaft when said cartridge moves along the mounting path; and an urging portion (185d, 3185c, 3185d, 4185c, 4185d, 5185d, 6185d, 7185d, 8185e, 9185e, 10185e, 11185d, 12185c) for applying an urging force to incline said coupling member (180, 980) relative to the rotational axis of said developer carrying member, characterized in that said developer carrying member is movable between the developing position in which it contacts said photosensitive member to develop the latent image and a retracted position retracted from the developing position, said coupling member (180, 980) is further capable of taking an at-spaced attitude inclined relative to the rotational axis of said developer carrying member in a direction different from that in the at-mounting attitude to engage with the main assembly driving shaft when said developer carrying member moves from the retracted position to the developing position in the state that said cartridge is mounted at the end portion of the mounting path, and said urging portion (185d, 3185c, 3185d, 4185c, 4185d, 5185d, 6185d, 7185d, 8185e, 9185e, 10185e, 11185d, 12185c) urges said coupling member (180, 980) to the at-spaced attitude. a photosensitive member on which a latent image is capable of being formed; a developer carrying member capable of developing the latent image; a coupling member (180, 980) capable of inclining relative to a rotational axis of said developer carrying member, wherein said coupling member (180, 980) is capable of taking a reference attitude in which the drive transmission is capable from the main assembly driving shaft to said developer carrying member when said developer carrying member is in a developing position in a state that said cartridge is mounted at an end portion of the mounting path, and an at-mounting attitude inclined relative to the rotational axis of said developer carrying member to engage with the main assembly driving shaft when said cartridge moves along the mounting path; and an urging portion (185d, 3185c, 3185d, 4185c, 4185d, 5185d, 6185d, 7185d, 8185e, 9185e, 10185e, 11185d, 12185c) for applying an urging force to incline said coupling member (180, 980) relative to the rotational axis of said developer carrying member, characterized in that said developer carrying member is movable between the developing position in which it contacts said photosensitive member to develop the latent image and a retracted position retracted from the developing position, said coupling member (180, 980) is further capable of taking an at-spaced attitude inclined relative to the rotational axis of said developer carrying member in a direction different from that in the at-mounting attitude to engage with the main assembly driving shaft when said developer carrying member moves from the retracted position to the developing position in the state that said cartridge is mounted at the end portion of the mounting path, and said urging portion (185d, 3185c, 3185d, 4185c, 4185d, 5185d, 6185d, 7185d, 8185e, 9185e, 10185e, 11185d, 12185c) urges said coupling member (180, 980) to the at-spaced attitude.