1. An image processing apparatus comprising: a control unit configured with a microcomputer, the control unit includes: a feature-quantity calculating unit that calculates feature quantities of target regions each indicating a tracking object in respective target images, the target images being obtained by capturing the tracking object at a plurality of time points; a provisional-tracking processing unit that performs provisional tracking of the target region by associating the target regions of the target images with each other using the calculated feature quantities; and a final-tracking processing unit that acquires a final tracking result of the target region based on a result of the provisional tracking, wherein the provisional-tracking processing unit includes an origin-image setting unit that sets the target images at a plurality of time points within a time range for which the provisional tracking is performed as origin images each being an origin of the provisional tracking, and the provisional-tracking processing unit performs the provisional tracking for each of the origin images that are set by the origin-image setting unit, and the final-tracking processing unit acquires the final tracking result of the target region by totaling a plurality of results of the provisional tracking performed for the respective origin images.