An image processor (3) includes: an image input unit (7) that obtains an image captured by an imaging device (2) installed on a vehicle; a vehicle information input unit (8) that obtains the distance between the vehicle and a road junction or curve from a navigation system (5); a recording unit (15) in which imaging information and driver information are pre-stored; a magnifying object recognition unit (9) that recognizes a certain magnifying object in the obtained captured image; and a composing unit (11) that produces, when a magnifying object is recognized, a composite image of an magnified image and the captured image. The composing unit (11) uses the distance obtained by the vehicle information input unit (8) as well as the imaging information and the driver information stored in the recording unit (15) to calculate an area in the captured image that is not an image of a blind spot for the driver, and produces the composite image such that the magnified image is superimposed on the non-blind spot area. This allows the driver to perceive information on the blind spot area and on the magnified image through a single action.