A toner cartridge includes a housing and a shutter inserted therein. The housing has a first partially cylindrical wall and a box-like portion that communicates with the first partially cylindrical wall. The shutter has a second partially cylindrical wall inserted inside the first partially cylindrical wall such that the second partially cylindrical wall is slidable on and concentric with an inner surface of the first partially cylindrical wall. The shutter has a supporting member that engages the housing to support the shutter such that the second partially cylindrical wall is in pressure contact with the first partially cylindrical wall. The supporting member may be in the shape of an arcuate member or ring that engages a part of the box-like portion so that the shutter is rotatably supported in the housing by the part and the first partially cylindrical wall. The housing has a projection or rib that inwardly projects toward the first partially cylindrical wall. The projection abuts the arcuate member so that the shutter is rotatably supported in the housing by the arcuate member and the first partially cylindrical wall.