A dust-proof structure for a measuring tool, includes: a case provided with an opening formed through a surface opposed to a protection plate thereof; a solar panel accommodated in the case through the opening of the case; an intermediate panel pressing an outer circumferential portion of the solar panel against a bottom wall of the case; a display device disposed at an inward portion of the intermediate panel and opposed to the solar panel with a gap; a cover attached to close the opening of the case; a screw used to secure the cover and the intermediate panel to the case; and a temporary-fixing unit disposed between the intermediate panel and the case, the temporary-fixing unit temporarily fixing the intermediate panel to the case while the outer circumferential portion of the solar panel is pressed against the bottom wall of the case.