An image forming apparatus includes an apparatus body, a cartridge attachable to and detachable from the apparatus body, a replenishment restriction portion configured to switch between a restricting state in which toner replenishment through a replenishment port is restricted and an allowing state in which toner replenishment through the replenishment port is allowed, a toner remainder amount detection portion, and a controller. The controller is configured to, when the replenishment container is attached to the replenishment port, maintain the replenishment restriction portion in the restricting state in a case where a second printable sheet number is larger than a first printable sheet number, with the first printable sheet number being obtained from a lifetime of the cartridge, and the second printable sheet number being obtained from a sum of the amount of toner accommodated in the developer container and an amount of toner accommodated in the replenishment container.