To provide a bearing installing structure which prevents the generation of vibration and noise when rotating a rotary body, and which can easily be assembled and manufactured, in the bearing installing structure for rotary body.

A bearing 23 with the shaft of an electrifying brush 5 inserted therein is pressed in and fixed to an installing hole 21 bored in a casing 16 of a drum cartridge via an elastic sheet 25. A projecting part 28 of the bearing 23 is fitted to a recessed part 27 formed in the installing hole 21. Even if an error is caused in a shape of the installing hole 21 and the bearing 23, since the elastic sheet 25 is embedded between these members, clearance is not generated between both, so that generation of the vibration can be prevented.