PROBLEM TO BE SOLVED: To provide a technique that enables an image pick-up apparatus for picking up images of a sample housing divided into plural areas to secure an effective field of vision in each image pickup position and restrain differences in color and brightness among plural picked-up images.SOLUTION: An image pick-up apparatus has a single illuminating optical system 100 containing a diffuser panel 103. First, the effective visual field area of an image pick-up unit 13 is determined while a sample housing unit is being irradiated with light from the illuminating optical system 100. Next, plural first image pick-up positions are so arranged that the effective visual field areas overlap one another along the sidewall of the sample housing unit. After that, plural second image pick-up positions are arranged in other areas than the effective visual field areas in the plural first image pick-up positions. After that, images are picked up in each of the plural image pick-up positions, and synthesized image
