An image processing device includes a processor including hardware. The processor implements an image acquisition process that acquires time-series images that were captured in time series, and a process that detects a change position, the change position being a position at which an object captured within the time-series images changes from a first object to a second object. The processor implements the process that extracts a feature quantity from each of the time-series images, determines whether the object captured within each of the time-series images is the first object or the second object based on the feature quantity, extracts candidate positions for the change position based on the determination results, and compares the candidate positions based on the determination results to determine the change position.
