Abstract: A toner composition is disclosed, which contains an inorganic powder having been subjected to surface treatment with a compound having an onium salt structure, containing no polymerizable unsaturated bond, and having a functional group capable of bonding to an inorganic substance. The toner composition satisifies both charging properties, such as rapid onset of charging, controllability of charge quantity and charge distribution, environmental stability, physical and chemical stability, and stability with time, and non-electrical requirements, such as powder fluidity, anti-blocking properties, and cleanability.