There is an image processing device to obtain more accurate depth information, based on a pattern-irradiated infrared image and a pattern-irradiation-free infrared image. The image processing device includes a pattern irradiation unit that irradiates an infrared pattern onto a surface of a target object; and an infrared image capturing unit that captures an infrared image. The pattern irradiation unit performs irradiation at a predetermined timing corresponding to an infrared image capturing unit's image capturing timing. The infrared image capturing unit obtains a pattern-projected infrared image in which the pattern irradiated by the pattern irradiation unit is projected on the target object, and a pattern-free infrared image in which the pattern is not projected on the target object.