A toner bottle stores toner in a cylindrical section having an inner
circumferential surface provided with a plurality of protruding portions
raised inward the cylindrical section. When the cylindrical section is
driven to rotate on its central axis, the toner is discharged from the
cylindrical section via an outlet. When cross-sections perpendicular to
the central axis of the cylindrical section are projected from a
longitudinal direction of the cylindrical section, the cylindrical
section has an inner circumference provided with one or more regions
where the protruding portions are not projected. This prevents the toner
from making contact with the protruding portions. Therefore, the toner
can be conveyed while suppressing the generation of frictional heat by
reducing the resistance between the toner and the protruding portions.