1. An imaging device, comprising: an imaging circuit to obtain image data by imaging an object; an image synthesis circuit to synthesize synthesis image data using the image data; an image synthesis estimation circuit to estimate whether an object possibly to be synthesized is included or not in the image synthesis circuit; and an image capturing instruction circuit to instruct the imaging circuit to capture an image, wherein the image capturing instruction circuit instructs the imaging circuit to capture a plurality of images according to an estimation result of the image synthesis estimation circuit.