The present invention relates to a driving mechanism for turning a photosensitive drum in an electrophotographic copying machine, which is provided with a brake loading means to brake the turning force of the drum, and is characterized in that the brake loading means comprises a brake loading device for a power transmitting means arranged between the drum and a motor and a brake loading device for the drum.The former device applies a predetermined frictional braking force to the turning of at least one follower axis in the power transmitting means and eliminates adverse effects of backlashes existing between the motor and the follower axis with respect to the turning stability of the drum. The latter device eliminates adverse effects of backlashes existing between the follower axis and the drum as the same above.