An image forming apparatus is provided with an apparatus main body including a developing device, a toner container detachably mountable into the apparatus main body and adapted to replenish the developing device with toner particles, and a lever member settable to a locking position by a biasing force of a specified biasing member to interlock the toner container with the apparatus main body while being pressed down against the biasing force of the biasing member to unlock the toner container. The lever member has an operation surface to be pressed, and the operation surface includes an inclined surface sloped downward toward a side where an operator would face.