1. An image evaluation apparatus that calculates an importance degree of each of a plurality of images including objects, the image evaluation apparatus comprising: a processor; and a non-transitory memory storing executable instructions, which when executed, cause the processor to operate as: a characteristic value calculating unit that calculates, for each of the objects appearing in each of the images, a characteristic value indicating a state of appearance of the object; a photographer extracting unit that, for each of the images, (i) determines a photographer of the image and (ii) calculates a likelihood degree indicating accuracy of the determination of the photographer; and an evaluation unit that calculates an importance degree of each of the images according to the characteristic values of the objects in the images and the likelihood degrees of the photographers of the images.