1. An image pickup device for picking up images in a plurality of wavelength bands, comprising: a first image pickup part for picking up an optical image in a near-infrared band, wherein the optical image in the near-infrared band is formed from light fluorescing from tissue; a second image pickup part for picking up an optical image in a visible-light band, wherein the optical image in the visible-light band is formed from visible light reflecting from the tissue when exposed to white light; a contour-image extracting part for performing processing for extracting a contour portion from a near-infrared image acquired by the first image pickup part; and a synthesized-image generating part for adding a visible image acquired by the second image pickup part and a contour image obtained through contour extracting processing by the contour-image extracting part at a predetermined ratio to generate a synthesized image.