Provided is a magnification observation device in which a focus of the imaging unit can be focused on the observation surface of the object in observation object region in a short period of time. An unit region of an observation object is imaged at a plurality of Z-positions by moving a object lens in the light-axis direction, the plurality of pieces of image data corresponding to the unit region are captured. An image of the observation object is displayed in the display unit as a navigation image. Shape data which indicates the position of the surface of the observation object in the unit region is generated. An observation object region on observation object is designated based on the navigation image. Based on the generated shape data, a focus of the object lens is on the surface of the observation object on the observation object region designated.