An image forming apparatus, comprising: a developing device which contains developer including toner and magnetic carrier and which develops an electrostatic latent image formed on an image bearing member using the developer; a toner supplying device (73, 81, 82) which supplies toner from a toner bottle storing toner for supply; a toner density detecting means arranged to detect information about a toner density of the developer contained in the developing device; a control means configured to control, in a normal mode, the toner supplying device (73, 81, 82) to supply toner at a toner supply amount based on a detection result of the toner density detecting means and a predetermined target toner density of developer to be contained in the developing device; a remaining amount detecting means arranged to detect information relating to a remaining amount of the toner bottle; and a replacement detecting means arranged to detect information for determining whether the toner bottle has been replaced, wherein the control means prohibits an image forming operation based on a detection result of the remaining amount detecting means, thereafter the control means immediately allows the image forming operation based on a detection result of the replacement detecting means, the control means is configured to execute one mode selected from the normal mode and a supply restriction mode, wherein the control means is configured to control the toner supplying device (73, 81, 82) in the supply restriction mode so that a toner supplying amount supplied by the supplying device (73, 81, 83) in the supply restriction mode when the toner density of the developer contained in the developing device based on a detection result of the toner density detecting means is a first toner density and the predetermined target toner density is a second toner density is smaller than the toner supply amount supplied by the supplying device (73, 81, 83) in the normal mode when the toner density of the developer contained in the developing device based on a detection result of the toner density detecting means is the first toner density and the predetermined target toner density is the second toner density, and the control means is configured to execute the supply restriction mode during a predetermined initial period after allowance of the image forming operation based on a detection result of the replacement detecting means and to execute the normal mode after the predetermined initial period. a developing device which contains developer including toner and magnetic carrier and which develops an electrostatic latent image formed on an image bearing member using the developer; a toner supplying device (73, 81, 82) which supplies toner from a toner bottle storing toner for supply; a toner density detecting means arranged to detect information about a toner density of the developer contained in the developing device; a control means configured to control, in a normal mode, the toner supplying device (73, 81, 82) to supply toner at a toner supply amount based on a detection result of the toner density detecting means and a predetermined target toner density of developer to be contained in the developing device; a remaining amount detecting means arranged to detect information relating to a remaining amount of the toner bottle; and a replacement detecting means arranged to detect information for determining whether the toner bottle has been replaced, wherein the control means prohibits an image forming operation based on a detection result of the remaining amount detecting means, thereafter the control means immediately allows the image forming operation based on a detection result of the replacement detecting means, the control means is configured to execute one mode selected from the normal mode and a supply restriction mode, wherein the control means is configured to control the toner supplying device (73, 81, 82) in the supply restriction mode so that a toner supplying amount supplied by the supplying device (73, 81, 83) in the supply restriction mode when the toner density of the developer contained in the developing device based on a detection result of the toner density detecting means is a first toner density and the predetermined target toner density is a second toner density is smaller than the toner supply amount supplied by the supplying device (73, 81, 83) in the normal mode when the toner density of the developer contained in the developing device based on a detection result of the toner density detecting means is the first toner density and the predetermined target toner density is the second toner density, and the control means is configured to execute the supply restriction mode during a predetermined initial period after allowance of the image forming operation based on a detection result of the replacement detecting means and to execute the normal mode after the predetermined initial period.