An image forming apparatus includes: an image carrier on which an electrostatic latent image is formed; a toner cartridge detachably mountable to the image forming apparatus, including a toner casing accommodating a developing agent, an opening/closing member which opens/closes an opening formed in the toner casing to discharge the developing agent, and an operation member operating the opening/closing member; and a developing unit to develop the electrostatic latent image by the developing agent discharged from the opening. The operation member can move between an open position for operating the opening/closing member to open the opening, and a close position for operating the opening/closing member to close the opening, and the operation member forms a part of a transport path of a recording medium in the image forming apparatus at the open position in a state where the toner cartridge is mounted in the image forming apparatus.