An image processing apparatus includes a memory that memorizes a plurality of pickup images in which an object has been picked up by varying an irradiation direction of a light; an extracting portion that extracts an area image of an area indicated by a user from each of the pickup images memorized in the memory; a calculating portion that calculates at least one illumination parameter for each area image by one of calculating an amount of edges from each extracted area image, executing a clustering process to brightness of each extracted area image, and executing a totaling process of totaling differences in brightness between the extracted area images; and a generating portion that generates at least one synthetic image by synthesizing the extracted area images with the at least one illumination parameter.