An image processing apparatus according to the present disclosure may operate in a normal state and a power saving state in which power consumption is smaller than that in the normal state. The image processing apparatus includes a detection unit which detects attachment of a detachable device to the image processing apparatus and detachment of the device from the image processing apparatus and a controller which controls execution of an interruption process in response to the attachment or the detachment of the device detected by the detection unit. The controller brings the image processing apparatus from the normal state to the power saving state after causing the detection unit not to perform the detection.