A charging system includes a rotatable member to be charged, and a rotatable charging member provided with electroconductive particles thereon and forming a nip part with the member to be charged and disposed in the nip part to charge the member to be charged. When the diameter of the member to be charged is defined as LD (mm) and the diameter of the charging member is defined as LC (mm), LD≦25 and LD×LC≧350. As a result,, in the charging system, and a process cartridge and an image-forming apparatus including such a charging system, an image-bearing member can be made small in diameter.