An image pickup apparatus has a construction in which a diffraction element is provided in an observation optical system. Zero-order light that is transmitted straight through the diffraction element and one of the +1st-order diffracted light and the -1st-order diffracted light that is diffracted by the diffraction element are imaged onto an image pickup surface of an image pickup apparatus. The imaging areas of the zero-order light and one of the +1st-order diffracted light and the -1st-order diffracted light that is diffracted by the diffraction element do not overlap on the image pickup surface of the image pickup apparatus. With this construction, a small image pickup apparatus that provides a high-resolution spectral image and a color image of an object can be obtained.