In a toner cartridge configured such that, by rotating a toner housing portion relative to a shutter in a state in which a first portion-to-be-engaged is engaged to a first engaging portion of a developing unit, relative positions of a cover and the shutter are displaced from first relative position, in which a closing portion opposes a second opening, to second relative position, in which the interior of the toner housing portion communicates with the developing unit through a first opening and the second opening, and a second portion-to-be-engaged is engaged to a second engaging portion of the developing unit, thereby being attached to the developing unit, a biasing member is provided in order to exert a biasing force for generating relative rotation between the cover and the shutter in a direction for displacing the relative positions thereof from the second relative position to the first relative position.