According to one embodiment, a measuring device for a sample liquid includes a container which stores the sample liquid, the container including a transparent or translucent optical component with an inclined surface to be brought into contact with the sample liquid, an optical sensor provided on a bottom of the container, which detects light from the sample liquid, and a measurement module which measures a concentration of a specific substance contained in the sample liquid, or a liquid height or liquid volume of the sample liquid based on a detected signal of the optical sensor.