PURPOSE: To provide an image forming device capable of handling changes in the environment caused by atmospheric pressure and elevation.

CONSTITUTION: An atmospheric pressure detecting means is disposed in the proper place of the image forming device and a controller 300 controls image forming conditions with an atmospheric pressure detecting signal. For instance, a control signal is outputted to the driving device 400 of a control motor adjusting the opening area of an air flow passage, to control the quantity of air discharged from a device. Moreover, each power source for a corona discharger is controlled so as to supply a voltage corresponding to the increase and decrease of the atmospheric pressure, so that the image forming device obtains a constant discharge current. Or the rotational speeds 700 of a fan for exhausting and a blower are controlled to execute the temperature adjustment and exhaust processing of the device.