A toner cartridge includes a toner container to store toner and two rotary agitation members to rotate to agitate toner in the toner container. The toner container has two arc-shaped portions adjacent to each other at an inner bottom wall of the toner container. The two rotary agitation members has edges to rotate along the two arc-shaped portions with rotation phases thereof shifted from each other. The two rotary agitation members are placed with rotation trajectories thereof partially overlapping each other.