An image processing apparatus for correcting a positional deviation between a plurality of images obtained in time series and performing synthesis processing on the plurality of corrected images determines a motion vector between the plurality of images, corrects the positional deviation between images on the basis of the determined motion vector, and generates a synthesized image by synthesizing the plurality of images subjected to the positional deviation correction. The image processing apparatus extracts a filter area in which filter processing is to be performed on the basis of a degree of inconsistency occurring when the positional deviation between the plurality of images is corrected, determines a filter kernel on the basis of an imaging condition, and performs filter processing based on the filter kernel on the filter area of the synthesized image.