1. A method for creating an image of a moving live-cell specimen using an observation apparatus comprising a microscope system and an information storage unit, wherein the microscope system comprises a stage on which the live-cell specimen is mounted and an objective lens that collects observation light from the live-cell specimen while focusing illumination light thereon, the method comprising: acquiring, with the microscope system, a micro image of the live-cell specimen; acquiring, with the microscope system, a three-dimensional macro image of an observation region that includes the live-cell specimen, by varying a relative position of the objective lens and the live-cell specimen in an optical axis direction, wherein a viewing range of the microscope system when acquiring the macro image is larger than a viewing range of the microscope system when acquiring the micro image; extracting identification information of the live-cell specimen included in the macro image by performing image processing on the macro image; storing, in the information storage unit, identification information of the live-cell specimen which moves and which is observed as a target; specifying, as a specified live-cell specimen, the live-cell specimen to which the extracted identification information corresponds in the identification information stored in the information storage unit; calculating an amount of movement of the specified live-cell specimen included in the macro image; and adjusting repeatedly, according to a movement of the live-cell specimen, a position of the viewing range of the microscope system in a direction that intersects an optical axis, based on the calculated amount of movement of the specified live-cell specimen, such that the specified live-cell specimen is included in the viewing range of the microscope system.