1. A position specifying system comprising: a light irradiation section that irradiates light to a first range and a second range of a physical body respectively; an image capturing section that captures images of an object existing inside the physical body, by means of the light irradiated to the first range and a second range; and a position specifying section that specifies a depth of the object from a surface of the physical body onto which the light from the light irradiation section is irradiated, based on a difference in the images captured by the image capturing section, wherein the position specifying section specifies that the depth is greater when a difference in at least one of an amount of blur, in a luminance value and in a contrast value between an image within the first range and an image within the second range of the object captured by means of the light irradiated at the first range is smaller.