To provide an image processing unit that can reduce the power consumption for cooling the entire image processing unit by activating a cooling fan for a reading device in a multi-mode and by eliminating the waste (excess cooling) of a cooling fan 29 for an image memory in a non-multi-mode.

The image processing unit has an image read section provided with a read device and its cooling fan 19, an image storage section provided with an image memory and its cooling fan 29, a heat pipe 31 that thermally connects the image memory and the read device so as to transfer heat from a high temperature side to a low temperature side, and a control means that activates both fans 19, 29 when either of the rear device and the image memory is in operation and the other is not.