A cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, said cartridge comprising: a developing roller configured to develop a latent image; a developing frame rotatably supporting said developing roller; a supporting member movably supporting said developing frame; a clutch (75; 170; 185; 270; 475; 575) configured to be switchable between a state in which a driving force for rotating said developing roller is transmitted and a state in which the transmission of the driving force is blocked, said clutch (75; 170; 185; 270; 475; 575) being rotatable by the driving force and including a locked portion (75d4; 175b; 275b; 475d4; 575d4); a control member (76; 176; 182; 576) for controlling the transmission and the blocking of the driving force by said clutch (75; 170; 185; 270; 475; 575), said control member (76; 176; 182; 576) including a locking portion (76b; 176b; 576b) engageable with said locked portion (75d4; 175b; 275b; 475d4; 575d4), said control member (76; 176; 182; 576) being configured such that said locking portion (76b; 176b; 576b) is rotatable between (a) a non-locking position in which said locking portion (76b; 176b; 576b) is retracted from a rotation locus of said locked portion (75d4; 175b; 275b; 475d4; 575d4) to permit said clutch (75; 170; 185; 270; 475; 575) to transmit the driving force by said clutch (75; 170; 185; 270; 475; 575), and (b) a locking position in which said locking portion (76b; 176b; 576b) engages with said locked portion (75d4; 175b; 275b; 475d4; 575d4) to stop rotation of said locked portion (75d4; 175b; 275b; 475d4; 575d4), thus blocking the transmission of the driving force by said clutch (75; 170; 185; 270; 475; 575); and an acting portion for acting on said control member (76; 176; 182; 576), said acting portion capable of rotating said locking portion (76b; 176b; 576b) between the non-locking position and the locking position, characterized in that said control member (76; 176; 182; 576) is rotatably supported by a supporting portion fixed on said supporting member, and said acting portion (32c; 532) is provided on said developing frame. a developing roller configured to develop a latent image; a developing frame rotatably supporting said developing roller; a supporting member movably supporting said developing frame; a clutch (75; 170; 185; 270; 475; 575) configured to be switchable between a state in which a driving force for rotating said developing roller is transmitted and a state in which the transmission of the driving force is blocked, said clutch (75; 170; 185; 270; 475; 575) being rotatable by the driving force and including a locked portion (75d4; 175b; 275b; 475d4; 575d4); a control member (76; 176; 182; 576) for controlling the transmission and the blocking of the driving force by said clutch (75; 170; 185; 270; 475; 575), said control member (76; 176; 182; 576) including a locking portion (76b; 176b; 576b) engageable with said locked portion (75d4; 175b; 275b; 475d4; 575d4), said control member (76; 176; 182; 576) being configured such that said locking portion (76b; 176b; 576b) is rotatable between (a) a non-locking position in which said locking portion (76b; 176b; 576b) is retracted from a rotation locus of said locked portion (75d4; 175b; 275b; 475d4; 575d4) to permit said clutch (75; 170; 185; 270; 475; 575) to transmit the driving force by said clutch (75; 170; 185; 270; 475; 575), and (b) a locking position in which said locking portion (76b; 176b; 576b) engages with said locked portion (75d4; 175b; 275b; 475d4; 575d4) to stop rotation of said locked portion (75d4; 175b; 275b; 475d4; 575d4), thus blocking the transmission of the driving force by said clutch (75; 170; 185; 270; 475; 575); and an acting portion for acting on said control member (76; 176; 182; 576), said acting portion capable of rotating said locking portion (76b; 176b; 576b) between the non-locking position and the locking position, characterized in that said control member (76; 176; 182; 576) is rotatably supported by a supporting portion fixed on said supporting member, and said acting portion (32c; 532) is provided on said developing frame. said control member (76; 176; 182; 576) is rotatably supported by a supporting portion fixed on said supporting member, and said acting portion (32c; 532) is provided on said developing frame.