To provide an image forming device capable of automatically regulating the image density at a low cost with high precision.

In an image forming device 1, a photoreceptor is uniformly charged to a charge potential by a charging part 3, and exposed in an exposing energy quantity modulated by an image data by an exposing part 4 to form an electrostatic latent image on the photoreceptor, the toner adhered to a developing roller is adhered to the photoreceptor having the electrostatic latent image formed thereon according to a developing bias potential by a developing part 4 to develop the image, the toner image is transferred to a transfer paper 9 at a prescribed transfer voltage by a transfer part 6 and the transfer paper 9 having the toner image transferred thereto is fixed by a fixing part. In this imaging process, the image forming device 1 detects the image density of the toner image on the photoreceptor by a density detecting part 7, an arithmetic control part 11 arithmetically compares the detected image density value with a reference image density value preliminarily stored in a memory part 12 and changes at least one of the charge potential of the charging part 3 and the developing bias potential of the developing part 5 or the exposing energy quantity of the exposing part 4 to regulate the image density.